Inform the search committee of another university about your current campus interview
I suspect that what you suggest is risky. It might bump them in either direction. If they are interested in you they will let you know, but probably on their own schedule. If you try to force the issue, it may be easier for them to say good-bye unless they really really want you. 

Some places have fairly strict rules about things and may not be able to say more than they have. That would result in a general answer, of course. 

I'd suggest you don't press too hard. Go to the other interview, evaluate what you hear there. If it sounds good, you can always ask for a delayed acceptance to see what happens at your preferred place. It might be acceptable or not, in which case you need to make a decision. 

I would also guess that they aren't so naive as to think that you aren't exploring other options. It is certainly assumed that you are.