Administrators to authorize pending group access requests

Some of our groups have MembershipAddWorkflow set to "Owner Approval". When users request access to one of these groups an authz workflow is kicked off asking the group owner for permission. If this person is absent there is no way of approving the request and it stays pending. How can FIM be setup to allow members of "Administrators" or "Group Admins" to allow these requests as well?

Thanks,
Mickey