The base Cyclone ENTERPRISE license allows up to 10 Groups. License-controlled "Groups" are inclusive of all levels of nested Sub-Groups. 10 Group add-ons can be added in any quantity at any time. The added Groups will be appended to the original EID.
You make check the maximum number of Groups (and Sub-Groups) allowed by your current license by navigating to Administration | Server | Licensing tab. It will be listed under "Maximum Number of Groups".
Note: Cyclone ENTERPRISE includes a Default Group. It may be renamed, but not deleted. And it counts as 1 group against the license.