Dilemma..

I foster rabbits and currently we have a bonded pair that came in together, but they've started to fight on and off. Now I know this is likely to be because they live next to other rabbits but I can't seem to stop the behaviour. The only thing that keeps them quiet for a long period of time is if I lock them in their hutch which is pitch black (it's actually a chicken coop that came with them). So I need to seperate them ideally, but keep them together to try keep their bond. The only other hutch/run combo I have is 4ft long and has a run double it's depth underneath it with ramp access. Should I put one in their up against their current shared enclosure? I know it's small but it'll the only thing I have left thats empty, but these rabbits are dutch, very big ones, and the spare hutch is a small 4ft if that makes sense? It's not very deep or high. I'm thinking of putting the "aggressor" in the smaller hutch

Don't really know what else to do, it winds me up and stresses me when I see or hear the female get chased around and her fur pulled.

Have you move them further away from the other rabbits or block them off better?

What is it that triggers the referred aggression? Sight? Sound? Smell?

Can you eradicate the issue in anyway?

Not too sure, that would mean putting one of the rabbits down the ally way :/ (in it's hutch) so it'll be a bit windyand a bit darker?