I've read some frog-keepers say you shouldn't house different species in the same viv. However, I'm not into frogs and haven't read a ton about them, so I don't know if that is a widely held standard or not.

The things to consider:

What are the exact husbandry requirements for each frog? Are they the same for each species you're considering? If not, then it is NOT a good idea to house them together.

Also...what are the territory needs for each frog, and are there any aggression issues that need to be considered?

Those are the first questions I'd be thoroughly researching before ever mixing species of anything in a viv. Sorry I don't have more specific answers, though!