Hi, I think its a great thing that you are taking in an older cat as these are the ones that dont get picked at the rescue centre, espcially the ones who might have a disability.
I only just got a bengal kitten a few weeks ago so I'm not too experienced in this area but I do have a domestic shorthair cat who is 4 now. You have to make sure that the already resident cat feels like he/she is still wanted in the home and you are not replacing them, yet let him/her know that the new cat is welcome buy showing them both affection.
I presume you situation is pretty much the same as two regular cats in a household, i dont think it matters that one is a bengal. You should google what is the best way to introduce your cat to a new cat.
Remember that as both these cats are older, their personalities are already formed, and that to your bengal, this is an intruder coming into HIS/HER house. So bear that in mind. Remember also that patience is KEY!
I wish you all the best, and you're picture looks lovely, you are blessed with such a great looking feline!