For consistency with other drivers and to make it easier to promote security group management methods to a top-level API in the near future, I would do the following:

1. Add two new methods - `ex_destroy_security_group_by_id(group_id)` and `ex_destroy_security_group_by_name(group_name)`
2. Add a wrapper method - `ex_destroy_security_group_by_id(name)` which calls ` `ex_destroy_security_group_by_name` underneath

As noted above, those methods will hopefully be promoted to a top-level API in the near-future and guaranteeing consistency and compatibility between drivers will be a bit easier then.