I'd suggest boost.
Doesn't matter what the composition is, as long as you have a high level on account A, who is boosting the others.

Boost a lot of combinations, during your RAF.

If you want to take the time to level a 5x group, without boosting, that's your prerogative; they're your accounts.
Just be sure to boost a lot of combinations, during the RAF period, so you have plenty of choices once RAF is over.