how to manage group permissions?

Hey all,
In my app users can create groups and the group creator can "kick" or
"ban" users. I want the creator to be able to grant other members of
the group to kick and ban.
This is how I want to do it:
I'm usgin acl_system2 and the creator can grant kick and ban
permissions to group members by creating roles "kick_group_id" or
"ban_group_id" for those users and then in the view I do:

<% restrict_to "(creator | kick_#{}) do %>
<%= link_to "kick this user out of the group",
<% end %>

is this a good way to deal with this problem or is there a (way)
better or simpler solution?

Thanx in advance