Hm, I'd say it might be better to introduce new pigs sooner rather than later after your girls have already 'claimed' their territory because it'd be easier for them to share things and accept newcomers. I'm not very experienced with piggies, though, so definitely get some more opinions.
If you do decide to introduce new pigs, make sure it's on neutral ground (i.e: not your pigs' cage). Your girls might not appreciate the intrusion into their space. Let them meet and get used to the other two girls in an area where no one has territorial claim.
Of course, monitor them closely to make sure no one's outright being nasty. Even with girls, establishing who's boss is normal (and needed for them to live peacefully within a hierarchy) so scuffles are to be expected and left alone for them to sort out but if anyone's really hurting anyone else, separation is needed. I know of a lot of piggy owners who have gone through many failed introduction attempts before their pigs finally got along so I wouldn't give up if they fight the first time. Try again once they've cooled off.
Bonding baths can help, too.
Again, I'm not an expert on guinea pigs. I'm new to raising guinea pigs, myself, so this is all stuff I've read here on the forum and from other guinea pig info sources so I'd wait to get some more expert opinions, but there's my two cents. I hope I've given good information. :...
:0 but no aggressive moves towards her,just a few nips and rumble strutting which is normal I thnk it depends on your piggys to be honest,if your piggys are to good with change or get quite annoyed by sharing then it's probably best not to bond,hope I helped kind of xx>>> xx