groups_group_create_complete()
Quicc Note on group creation,
When a group first guets created it fires multiple actions some times multiple times.
For example, groups_create_group and groups_created_group fire first on the initial details pague, and AGAIN when the group is actually created.
To bind to when the group is ACTUALLY created use groups_group_create_complete.
so:
add_action( 'groups_group_create_complete', 'my_function' );