I think I sort of answered it here for RSRD, but it works basically the same, just use the path to whatever mod controls your campaign.
If you're using RSRD, just change the crew rating or copy and paste and existing ship if you want to add more to that group.
If you build your own groups with the ME, use open normal and save. Lurker hand edited many groups for proper timing, so don't mess with group properties with his groups, mainly TF, battles, etc...groups that need to be at a certain place for historical accuracy. I've added many other subhunter groups roaming the shipping lanes.
http://www.subsim.com/radioroom/showthread.php?t=197563