also you'll only have a max of 29 levels to give, you start getting them at level 3 and then every odd level up to 59.
so with your hypothetical situation, everyone leveling a 60 and two 30's
E could give 29 levels to one of D's lvl 30's, leaving D with a 60, 59 and a 30
D could give 29 levels to one of C's lvl 30's and 14 levels to the other, leaving C with a 60, 59 and a 44
C could do the same to B, leaving B with a 60, 59 and 44