rabbits and guinea pigs together

Question
I have two supposed female rabbits and 1 female guinea pig,(that could possibly be pregnant). My two rabbits have just started fighting, so they have been separated, one in particular seems to be very fond of the guinea pig. if she is with baby will she be ok, housed with the rabbit or should I take her out on her own?

Answer
No
You cannot keep the rabbit with the guinea pig.
A kick from a rabbit can kill the guinea pig. Ribs and backs and legs have been known to be broken by rabbits.
Also rabbits and guinea pigs are in need of their own diet. A guinea pig diet is higher in protein and must contain vitamin C as they cannot produce their own vit C. Rabbits have also been known to starve guinea pigs because of their rate of devouring the food.
Rabbit pellets can contain coccidiostats to prevent coccidiosis in rabbits and this ingredient is fatal to guinea pigs.

Keeping rabbits and any other guinea pig away is more so if your guinea pig is pregnant. She will need a lactating pellet to help her to keep her strength up and produce the right amount of milk for when the babies are born. She will also need a good vegetable diet and plenty of unlimited hay and water.
She will also need plenty of veg, lactating pellets and water after the guinea pigs are born. The babies will be eating vegetable near enough straight away/within 24 hours of birth so she must not miss out on her share.
With a rabbit in the cage she may also stress and abort her young. She needs peace and rest now. When her babies are born if there are females they can continue to live with her for the rest of her life. Any boars will needs separating after weaning.

If your doe's have just reached maturity i would suggest you have them spayed to prevent unwanted litters, cancer and reduce the hormone level which could be causing the aggression.
Sisters have a 65-70% chance of fighting at maturity.
You could try re bonding them slowly after 3-4 months of spaying