Hi and welcome!
Please place hay (which should make over 80% of the daily food intake) close by where they are sitting and be careful with feeding veg in case neither they nor their mothers have had it at the commercial supply breeder's or in the shop and their tummies are not used it.
it would be great if you also provided hiding places - even if it is just pegging a couple of old handkerchiefs to the bars or cutting a couple of door openings into a small cardboard box.
Otherwise leave them be and avoid any predatory behaviours/triggering their prey animal instincts.
You may find the various detailed tips and information in our guides helpful; especially understanding how your babies see things, how prey animal instincts work and how you can use their own body language and social expectations to invite them as a welcome part of your group in order to give them identity and a place they belong.
You can access all the relevant guides via this shortcut here, including what to look out with in new piggies from a place without quarantine etc. (sexing and the most common problems pet shop piggies come with):
Settling In And Making Friends With Guinea Pigs - A Guide
Please be aware that when you choose pet shop piggies for looks and not for who they are hanging out with, your youngsters may not necessarily be best of mates.
All the best!