Is this normal behavior when introducing new guinea pigs? Please help!?

[Lucy ♥]

We have two female guinea pigs. They are now around 3-4 months old. We have had them since they were 6 weeks old. They were the last two in the shop so they have known each other since they were tiny, but they are not related. They get on great. They really do love each other.

On Sunday we got another guinea pig. She is a female and is 6 weeks old.

We named the new one Janet, and the old ones are called Pippa and Tilly.

We put Janet in Pippa and Tilly's cage and this is the behavior we saw - there was quite a bit of jumping going on and quite a bit of running. Also Pippa and Tilly went up to Janet and kept sniffing her, like really sniffing her - they were getting there nose's right into her. Also, Pippa seemed to run up to her, and i don't know how to explain it, start on her? Not aggressively, but she would seem to make Janet run away from her. But they didn't bite or fight with her or anything. Is this normal?

Janet isn't living in with the others at the moment, she is in a separate cage. But we like them to meet everyday. So we put them all in the run together, and they run round together and they look quite happy.

Thanks for your help everyone