MDM - Shopping List Acess to Users

Hi,

Please help with the following situation:

User A - Catalog XPTO , with catalog- named-search AA

User B - Catalog XIOW, with catalog- named-search BB

User A, creates a Shopping List, called BTW that is shared.

User B sees the Shopping List BTW and the articles that are listed are not contained in his named-search.

In this situation, User B can't buy the itens of this Shopping List, as they are not part of their catalog BB.

How can we cut the acess of these itens, for user B?

I mean, User B can't buy them, so there must be any error ou any way of not showing them... Do you know any?

Thanks in advance,

Maria