Can you put a small breaker panel after a 30 amp breaker from main panel in the house?
It sounds like what you want is a sub-panel (http://www.wikihow.com/Add-a-Subpanel). You will need to check for local regulations pertaining to exactly what you need to install, but all of the materials should be available at the local big box store. Also, make sure that you size the breaker at the main panel correctly (you mention 2-4 15 amp breakers, anything more than 2 with a 30 amp breaker would be a no go.)