Given Jack's history (and USG ties), it could be he started trying to found the group with Charon (who he met in some hell-hole or another), but got static from the USG. Reaching out to try and smooth things over (heavy weapons licenses, explosives permits, authorization to operate stateside, etc.), their ideas landed on Andrea's desk. Depending on how long ago the group was founded, she could have had her family blown up and then used her clout and some favors owed (plus skeletons staying buried) to get the group okayed in exchange for their first contract: be part of her private war on the cartels. After she "cleaned up" with all the help she dug up, she was given "detached duty" with what many would see as her "pet project". Sounding good?
On a side note, Marco, do you have a problem with me using my Mastermind minions to represent temporary "trustworthy allies" that she taps for whatever the team needs covered (or as a tac-team to save us should we get captured and someone saw it coming)? I would explain this as her reaching out to all the contacts she has built over the years, the people who owe her favors, or even all the other people who joined her in her war on the cartels...which is why they can show up just as long as needed anywhere before going back to their dayjobs. I would roleplay this; if I didn't call/plan ahead, then they aren't available.
And anyone need any sweet gear before we get IC?