diff --git a/app/models/ext_management_system.rb b/app/models/ext_management_system.rb
index a78bf67dae0..61ca888cb0d 100644
--- a/app/models/ext_management_system.rb
+++ b/app/models/ext_management_system.rb
@@ -64,10 +64,6 @@ def self.api_allowed_attributes
   has_many :resource_pools, :foreign_key => "ems_id", :dependent => :destroy, :inverse_of => :ext_management_system
   has_many :customization_specs, :foreign_key => "ems_id", :dependent => :destroy, :inverse_of => :ext_management_system
   has_many :storage_profiles,    :foreign_key => "ems_id", :dependent => :destroy, :inverse_of => :ext_management_system
-  has_many :physical_racks,      :foreign_key => "ems_id", :dependent => :destroy, :inverse_of => :ext_management_system
-  has_many :physical_switches,   :foreign_key => "ems_id", :dependent => :destroy, :inverse_of => :ext_management_system
-  has_many :physical_chassis,    :foreign_key => "ems_id", :dependent => :destroy, :inverse_of => :ext_management_system
-  has_many :physical_servers,    :foreign_key => "ems_id", :dependent => :destroy, :inverse_of => :ext_management_system
   has_many :customization_scripts, :foreign_key => "manager_id", :dependent => :destroy, :inverse_of => :ext_management_system
 
   has_one  :iso_datastore, :foreign_key => "ems_id", :dependent => :destroy, :inverse_of => :ext_management_system
diff --git a/app/models/manageiq/providers/physical_infra_manager.rb b/app/models/manageiq/providers/physical_infra_manager.rb
index bb432be099c..c377a45384f 100644
--- a/app/models/manageiq/providers/physical_infra_manager.rb
+++ b/app/models/manageiq/providers/physical_infra_manager.rb
@@ -2,12 +2,18 @@ module ManageIQ::Providers
   class PhysicalInfraManager < BaseManager
     include SupportsFeatureMixin
 
-    virtual_total :total_physical_racks,      :physical_racks
-    virtual_total :total_physical_switches,   :physical_switches
-    virtual_total :total_physical_chassis,    :physical_chassis
-    virtual_total :total_physical_servers,    :physical_servers
-    virtual_column :total_hosts,              :type => :integer
-    virtual_column :total_vms,                :type => :integer
+    has_many :physical_chassis,  :foreign_key => "ems_id", :dependent => :destroy, :inverse_of => :ext_management_system
+    has_many :physical_racks,    :foreign_key => "ems_id", :dependent => :destroy, :inverse_of => :ext_management_system
+    has_many :physical_servers,  :foreign_key => "ems_id", :dependent => :destroy, :inverse_of => :ext_management_system
+    has_many :physical_switches, :foreign_key => "ems_id", :dependent => :destroy, :inverse_of => :ext_management_system
+
+    virtual_total :total_physical_chassis,  :physical_chassis
+    virtual_total :total_physical_racks,    :physical_racks
+    virtual_total :total_physical_servers,  :physical_servers
+    virtual_total :total_physical_switches, :physical_switches
+
+    virtual_column :total_hosts, :type => :integer
+    virtual_column :total_vms,   :type => :integer
 
     class << model_name
       define_method(:route_key) { "ems_physical_infras" }
diff --git a/app/models/physical_chassis.rb b/app/models/physical_chassis.rb
index 303dcf159cd..6fefe0bd3a2 100644
--- a/app/models/physical_chassis.rb
+++ b/app/models/physical_chassis.rb
@@ -1,5 +1,6 @@
 class PhysicalChassis < ApplicationRecord
-  belongs_to :ext_management_system, :foreign_key => :ems_id, :inverse_of => :physical_chassis
+  belongs_to :ext_management_system, :foreign_key => :ems_id, :inverse_of => :physical_chassis,
+    :class_name => "ManageIQ::Providers::PhysicalInfraManager"
   belongs_to :physical_rack, :foreign_key => :physical_rack_id, :inverse_of => :physical_chassis
 
   has_many :physical_servers, :dependent => :destroy, :inverse_of => :physical_chassis
diff --git a/app/models/physical_rack.rb b/app/models/physical_rack.rb
index ff1129113cf..7a81c38b7fa 100644
--- a/app/models/physical_rack.rb
+++ b/app/models/physical_rack.rb
@@ -1,7 +1,8 @@
 class PhysicalRack < ApplicationRecord
   acts_as_miq_taggable
 
-  belongs_to :ext_management_system, :foreign_key => :ems_id, :inverse_of => :physical_racks
+  belongs_to :ext_management_system, :foreign_key => :ems_id, :inverse_of => :physical_racks,
+    :class_name => "ManageIQ::Providers::PhysicalInfraManager"
 
   has_many :physical_chassis, :dependent => :nullify, :inverse_of => :physical_rack
   has_many :physical_servers, :dependent => :nullify, :inverse_of => :physical_rack
diff --git a/app/models/physical_server.rb b/app/models/physical_server.rb
index 5241ec3890a..7215caed0e7 100644
--- a/app/models/physical_server.rb
+++ b/app/models/physical_server.rb
@@ -17,7 +17,8 @@ class PhysicalServer < ApplicationRecord
   }.freeze
 
   validates :vendor, :inclusion =>{:in => VENDOR_TYPES}
-  belongs_to :ext_management_system, :foreign_key => :ems_id, :inverse_of => :physical_servers
+  belongs_to :ext_management_system, :foreign_key => :ems_id, :inverse_of => :physical_servers,
+    :class_name => "ManageIQ::Providers::PhysicalInfraManager"
   belongs_to :physical_rack, :foreign_key => :physical_rack_id, :inverse_of => :physical_servers
   belongs_to :physical_chassis, :foreign_key => :physical_chassis_id, :inverse_of => :physical_servers
 
diff --git a/app/models/physical_switch.rb b/app/models/physical_switch.rb
index 66878d1b563..e2232872f57 100644
--- a/app/models/physical_switch.rb
+++ b/app/models/physical_switch.rb
@@ -1,10 +1,11 @@
 class PhysicalSwitch < Switch
+  belongs_to :ext_management_system, :foreign_key => :ems_id, :inverse_of => :physical_switches,
+    :class_name => "ManageIQ::Providers::PhysicalInfraManager"
+
   has_one :asset_detail, :as => :resource, :dependent => :destroy, :inverse_of => :resource
   has_one :hardware, :dependent => :destroy, :foreign_key => :switch_id, :inverse_of => :physical_switch
   has_many :physical_network_ports, :dependent => :destroy, :foreign_key => :switch_id
 
-  belongs_to :ext_management_system, :foreign_key => :ems_id, :inverse_of => :physical_switches
-
   def my_zone
     ems = ext_management_system
     ems ? ems.my_zone : MiqServer.my_zone