You probably could get away with it just fine if you collected them yourself from the same habitat. I have found them sitting side by side under patio umbrellas and window shutters in my area and they aren't aggressive or toxic to one another. The reason species mixing is usually discouraged isn't because it is impossible to make it work, it is generally discouraged because it is easy to mess things up if you don't know exactly what your doing. As such it is usually one of those things that if you have to ask instead of knowing if it would be ok or not you should probably get more experience before trying it.