Wrong sending several instruments to one Reverb?

I like the idea of using the "same room" for many instruments - I know that's a common thing to do as well.

But I was wondering - is it a faulty approach to send some instruments to the same reverb?

What I mean is - will the return signal from the reverb be cluttered and smeared when it has to deal with several instruments? or how will the reverb return react to things like that?

let's say I wanna have the same room on both a string pad and a piano - is it wise to send them both to the same reverb - or is it better to run two instances of the same reverb with the same settings - and only send one instrument to one reverb?

I'm talking ITB.

any ideas?