Rabbits and guinea pigs should not be housed together as guinea pigs can get some diseases from rabbits, the two species have different nutrition requirements, and they can bully each other.
Both rabbits and guinea pigs are social species, so they should be kept in a pair or group of with other compatible animals of their own species.
Generally, rabbits should live as part of a bonded pair of rabbits; this is a process that takes some time and patience but, if successful, will hugely improve your rabbits’ quality of life. See our article on bonding rabbits to each other, and to people for more information. Make sure both rabbits are desexed to prevent unwanted litters of baby rabbits and to help prevent fighting.
Guinea pigs need to be kept with other guinea pigs. In their natural habitat, they live in herds and communicate frequently with each other with sounds and body movements. Your guinea pigs should be kept in groups of at least two individuals. Make sure that the guinea pigs are desexed or that both animals are of the same sex to avoid having any unintended litters of baby guinea pigs.