bonding trouble

(Hamilton)

Hi I'd appreciate some advice.
I have two rabbits, one is a neutered boy nearly 5 months old, and the other is a baby girl, about 9 weeks so not spayed at the moment.

Both have lived with other rabbits happily, so I hoped they would take to each other. I used to have another boy rabbit who unfortunately died.

I've found I'm missing him a lot, because my two boys used to love each other, but with the new girl I have to keep them separated because they attack each other. I've had two bad bites off each of them when separating them. When they're on their own with me they're lovely, but horrible when they're put together.

It's really upsetting because I don't want to have to re-home the girl, but I don't want to keep getting bitten and the point of another rabbit was company for my bereaved male rabbit

has anyone had similar experience?