User having team member role can access contract in BU he is not authorized.

We are using Customer contract team member role, how can we control:

1. User can view contract in BU's he is not authorized.
2. User should not be viewing contract of person higher in authority within same BU.

Also, I have edited to remove data security on contract search and view to : only view that contract that is a team member and have full access.

I need to restrict user for accessing contract in BU's he is not authorized too.