I have a big c&c cage for my girls... and they can free range around the dining room, kitchen and hall.
They all seem to be doing their own thing and are not cuddling up much together. They all eat together as I think they realise that with so many it's eat and get on or else you get nothing but left overs.
One of my girls seems to be more isolated then the rest. She's the only one who constantly climbs underneath the fleece bedding. She lived alone for quite a few months before we got her and didn't have any social skills at all. While she now grasps the basic of guinea pig social etiquette (for example you can't just run straight through another pig), she still needs some quiet time on her own. When I first got her I bonded her with a baby pig and they lived apart from the rest of my sows (the plan was to foster them and find them a lovely new home but they stayed for good). The baby who is very social was however always desperate to get into the big cage and she's a much happier piggie now that she lives with the rest. And Fiona, the older pig, seems a lot happier too even though she appears at times isolated.
Sorry to go on for so long... What I'm trying to say is that your piggy might get on fine with the baby, but there are no guarantees that they will be close. Also it can take quite a while for piggies to settle in and you might find that she will eventually gets closer to the rest of your group. Or else she might just be a bit of a loner who while enjoying the company of the rest, also enjoys some quite alone time.
I think my preferred option would be to have all piggies living together provided they get on fine and none get bullied.