"Cannot be booked at same time" GPLv3 v2.8.6.1

[daj1u06]

The help wiki has the following section:

Preventing Resources From Being Booked at the Same Time

Resource Relationships can be used to define resources that cannot be booked at the same time. To configure this, add a resource within the Cannot Be Booked at the Same Time section. Once set, all non-administrative users will be prevented from booking a resource if any other related resource is booked at the same time.

Where is this option toggled, I can't find it anywhere?

Thanks.

[daj1u06]

This is what I see for any resource, there is no "cannot be booked at same time option".