Ok I am not saying to just chuck them in and see what happens that would be bad pet ownership all I am saying is that they should be conditioned to seeing, hearing and smelling each other probably not in the same cage together like I have with Bailey and Shida (they are very similar in size) but I would start with having both cages in the same room at different ends to each other then over a few weeks slowly move the cages closer so both animals are using their senses to "see" each other this will make then curious not stressed but keep an eye out for sins of stress if they are not coping take them away and start again a bit later. Being able to have the cages next to each other in the long run can be a very good thing if car trips are nessissary or they need to be kept in close quarters whilst moving. I believe all pets should be taught to accept each other