How to add new field in search criteria

Hi, Under User List I want to add a search criteria by the name 'members'.

members are basically users who are friends after accepting friend request in uddeim component.

I added 'friends', 'relatives' etc. under 'type' for members. And want to search them by 'type'.

How to do this ?

Hope am clear enough to explain the problem.

Can anybody guide me the table where 'Connection Types' are stored?