In addition to Eliasz's recommendation you can also do these:
One of the easiest ways to rename the AP group is the cloning option on the CLI
(MC1-Sunnyvale-3600) (config) #ap-group <name of the new AP group>
(MC1-Sunnyvale-3600) (AP group "new") #clone <the AP group that has to be cloned>
Say you have an AP group called RAP-ap-group and you have 10 RAPs in that group, Now if one AP has to use an additonal SSID or a different password for one of the current SSIDs then , an easy option to do this is using the AP specific configuration.
If you want employee SSID on RAP 9 to use a different password then create a new VAP with new SSID profile (this will have the new password) and AAA profile (you can use the old AAA profile). Now this new VAP can be added only to RAP-9 and the old VAP can be removed from only RAP-9 using the AP specific config.
However, if 5 out of 10 RAPs require password change on the employee SSID or require an additional SSID, then it is better to create a seperate AP group. In this case depending on the number of changes required you can either clone and edit the AP groups or create new AP groups.
Regards,
Sathya