Emm.. I would say, why not work out on the Legion 69 logo 1st,
let individual Team have their own design for their team T-shirt (and player's name optional)
Every team under legion 69 shall then add on the Legion 69 logo to the team t-shirt.
This will basically let every team to maintain their own image while having the legion 69 logo as a family.
This definately sound more costly because of the quantity is lesser.. but imagine new member comes and go.. the printing for t-shirts will still go on.. we probably just pay little bit extra for the mould for the 1st time.. (1st time is never cheap..