So for two teams the ideal way would be:

Accounts:
Veteran -> A -> B -> c -> D -> E

TEAM 1:
A,B,C,D,E

Team 2:
V,A,B,C,D


That way once Team 1 levels up they will have 30 levels each that can be granted to a member of Team 2. Once done you can transfer the character on E to V to go back to having 5 accounts to pay for instead of 6.