RFQ: Limit Maximum Products per vendor by membership
 

I want to be able to limit the maximum number of products a provider can have in the store catalog at any one time based on the membership I've assigned to them. For example,

Bronze Membership: maximum of 15 items
Silver Membership: maximum of 25 items
Gold Membership: unlimited items

I can manually assign the memberships, but I need xcart to pop up a message if they try to add one more product than their current membership allows.

This should be a simple database query with an if then else statement, but I have no idea how to write it.

Any gurus out there?