I could tell so many stories

. I have owned 16 guinea pigs within the last eleven years.
Currently I have a group of three females and one neutered male.
The Ladies are 5 years, 2 years and 2 months old and the husboar is a bit older then 2 months.
I also had a boar group some years ago (all boars neutered, as it’s normal in Switzerland) and a totally mixed group.
The most important tip is patience. Bonding always takes time. Plus never separate during bonding process except there is (much) blood.
I had a really bad fight once between two boars of a boar trio, but after that they got along as if it never had happened.
I would actually always have the boars neutered, it doesn’t change their character but if they fell out they could be bonded with a girl right away.