3 pigs behaviour

Question
i have three guinea pigs. rusty, shredder and stripes. i have 2 questions.
1. how do i know that two of my guinea pigs wont leave one out of everything and so it will be all alone. is there anything that i can do to make them stay with each other and not leave one out?
2. My guinea pig rusty keeps on going up to shredder and stripes and nibbling them on the ear. is she being affectionate or is she biting them?
please help me

Answer
Well nibbling is generally showing dominance and is okay as long as she doesn't start hurting them. Generally all 3 guinea pigs should get along just well and there's really nothing that you can do to prevent one guinea pig from being left out of the group. Generally they fall in packs and play with each other so I really don't think you need to worry about one guinea pig being left out. If one guinea pig starts acting funny and only sits and corner and starts sleeping a lot and is not eating and drinking than that guinea pig could be sick and should see a vet. All in all though guinea pigs do great with a companion or two and I think as long as there is enough room for all three they should be happy.