Never more than two boars no matter one anyone may say, this forum is littered with fights, fall outs and disaster when people have attempted it
Some info on groups here
Adding More Guinea Pigs Or Merging Pairs – What Works And What Not?
We started off with two girls, Pitch & Putt the piggies in my avatar.
After we lost them we had another two ladies Cookie & Treacle and also had a single special needs piggy Megan who could live with other piggies due to various medical conditions.
After Treacle died we got cookie two friends Vimto & Sarsaparilla - went to a trio we soon added Widget and had for girls for around 2 years before losing Cookie, then Sarsaparilla and a month later Vimto
We are now at two again with Widget and Chickpea
So feel we have organically grown over the years
Pairs are often very close and all the pairs we have had have had lovely bonds. Our Foursome at one point was amazing to watch the interactions of our little herd and great fun. The one thing I will say is don't go too crazy to start with, we had two poorly piggies at once when we had four and with syringe feeding etc... it became crazily emotionally and physically draining,
You could go for a trio of girls, some rescues have trios in to go together or can bond three sows together for you.
Same with a Husboar and two girls - Never two boys and a girl though