Associate Vendor to Project

Associate Vendor to Project

We would like to keep our accounts section strictly for customers and not include our vendors.  We want our vendors to all be listed under the vendors ribbon.  The reason for this is we want everyone in the company to be able to access all of the vendors but we don't want everyone to access all of the accounts.    

The problem I'm having is I would like to associate vendors to projects but it says they have to have an account.  Is there a way to turn this requirement off.  I tried to find it in customization and wasn't successful.

Would be most a most welcome feature 

Linda