Boars are better as pairs , trios are fraught with problems.
Your new baby boar can leave Mum quite young (often they are weaned at 4 weeks .....they are fertile at this age and will think nothing of mating with their own mums 
) and put with other boar piglets till maybe 6 weeks.
But once they are weaned and eating solid food well they don't need Mum.
You'd need to do the whole Neutral Territory to bond them. Clean (no pig smell) neutral space . We used to use a paddling pool .
You need as big a space as possible with males , the beauty of C&C is you can add and alter it.
I miss our guinea-pigs , DD started with two brothers (year old) and we fell into the spiral from there , emerging eight years later when our last sow died in April.
If I had a choice of male or female , the males are cuddlier and tidier . We had two boars that were castrated (not at the same time) who had wives .
Piglets are so cute and fragile . Make sure you see them when they're born, they are teeny replicas of themselves with huge feet , eyes and ears. All fully furred , eyes open, teeth, ready to go.............then they turn into lardy adults.
Read up loads on boar behaviour , the Terrible Teens . There's ways to minimise it and make things smoother for your new boys.
Good Luck 