Since the kde-sig list already exists, you are all set :)

https://admin.fedoraproject.org/accounts/group/view/kde-sig

Basically is left:
* Create the bugzilla account for the list's email (if not done already)
* Set the mailing address in the group in FAS
* Start giving ACLs to {{{group::kde-sig}}} where desired :)

Let us know if there is anything else we can do to help.