You never know how long it's going to take. It might not ever work to be honest. Hopefully it will work out but it's possible that it might not.
When I introduced Shady and Behbet it took a week or two. Then when I added Yoshi, Shady fell in love with her right away, but it was months and months before I could get Behbet to accept her. But finally they all love each other.
I wouldn't let them stay in the same cage if they are fighting, they could kill each other. You need to make sure that they are getting along before you leave them alone together. Just keep the cages next to each other, swap the pouches so they have each others scent all the time.