New mates for my 2 lovebirds

[Ermis238]

So I've had a pair of lovebirds for a couple of years now and even though at first I bought them as a breeding pair they later turned out to be 2 females. In the beginning, there were some fights but after a few weeks, things seemed to start calming down. So a few weeks ago I decided to get 2 males to breed them. Today their 2-week quarantine ended and I brought them to the same room. I put them in a breeding cage with a separator between the males and the females. One of the females has always been "the calm one" and the other is a bit more aggressive but nothing too crazy. So now that they see each other I noticed that the more aggressive female is trying to bite the males if they come close to the separator exactly the same way she did with the other female in the beginning. I'm guessing she is a little bit territorial or she is trying to assert dominance so I would like some advice on how long should I keep them with the separator before I put them together? And also how should I separate the 2 females to make it as less stressful as possible so I can pair them up with the males (they have been together for 2 years)?