how to allow a user to make multiple cck groups

hello, im working with cck on a form and cant figure out how to make the group be able to have multiple listings.

here is what im trying to do:

studio artist (group)
artist name (cck field)
instrument played (cck field)

how do i allow the user to input multiple studio artists? like:

studio artist (group)
artist name (cck field)
instrument played (cck field)

add another studio artist (button)