This add-on adds support for a "member group" field within an item_options / price modifier field.
Installation: move file to system > expressionengine > third_party
Go to add ons > field types in ExpressionEngine's settings, and enable this field type. Go to the channel fields admin and add this field type to your products channel.
This add-on is provided as-is at no cost with no warranty expressed or implied. Support is not included.