Help on act_as_ferret

My name is santoshkumar r Patil. I am using ferret for searching.
I am using mult_search for searching a query on multiple modal and there
are different conditions on different model.
User.multi_search(search_query+" AND NOT is_deleted:1
And I have to condition “is_visible = true” on program model.

How can I modify above query.

Can we you INNER JOIN query in find_by_contents and in mult_search