Adding a Samba network to a larger domain

[Qweasda]

I have a Samba network, connecting 4 computers together. I now need to add this to a larger domain that holds all the building's networks in one domain. (i.e. you view the one large domain that lists all (apr.) 70 networks). Right now it is its own domain.

A point to the right direction or some help would be nice, thanks.