Introductions Question about pairings

Yes, that's a good plan. The baby boy needs to be separated from his mom and sisters at 21 days of age.

Was the male out of the cage when the pups were born? If not, she's likely pregnant again, as they can get pregnant within minutes of giving birth.

When you separate them, if you put the cages adjacent to each other, put a lid on the girls' cage A determined male can push up the lid on his own cage, but can't lift the lid on another cage.

To go more in depth boy guinea pigs typically don’t do very well on trios and that’s because boy guinea pigs in the wild almost always live with a group of girls obviously we can’t do this in captivity unless the boys are neutered because they’ll breed in my opinion the best option would be to neuter the adult boy and put him with the two baby girls and the mom they could all live in a large cage and the two baby could boys could live in a separate cage I would like to point out though taking on that many guinea pigs can be very hard I wish the best of luck to you

@oreo the piggy is right that trios of males don't work. But you don't have a trio, @rhard, you've got a pair of males, and that should work just fine.

Will the mom and sisters work well together?

Yes. Sows generally get along very well. Maybe one in a thousand will be too bitchy to get along with other females, but it's very rare.

The one issue that can arise if one or more develop ovarian cysts, which generally happens only after they're middle-aged. They exhibit dominance signs, and can make life very unhappy for the others in the cage. They can, however, be treated for the cysts, either by surgery or possibly hormone treatments.