I’m not all that experienced, however when Honey was still alive, he and Little (dominant pig) lived together. Little would always be barbering Honey, sometimes more so than other times. There was a long period where every time Honey would drink, Little would be pulling out Honey’s fur whilst he would squeal in protest. He never did anything about it as he wasn’t top pig. They got along alright in general, they could’ve been better matched though. Since Honey died and Little was bonded with Peanut in June/July, Little is still top pig but has never demonstrated barbering since. The bond between them is a lot stronger, they get along better. It’s funny how Little would try and barber Honey just about every day, to then never try to barber Peanut at all.
I think that whilst the barbering isn’t doing much harm to the bond, the submissive pig may be just having to tolerate it to keep the peace. If you were to separate them, and have them bond with a pig of their choosing, you may find this behaviour stops altogether as they ultimately like the pig their with more. If you feel like they would benefit from new friends, then I’d say go for it. But if you think they’d do okay staying together, then see how it goes