To get RAF, you need to meet all of these:

a) Grouped with a toon whose account is directly linked to your own.
b) Within a certain proximity to that toon.
c) Within +/- 4 levels of that toon.
d) The mob/quest cannot be grey to either of you.
e) You must both be level 59 or lower.

If you are linked: A - B - C - D - E
But grouped like this: A - C - E
Then no one gets RAF, since there is no direct link between accounts.

Similarly: A - B - C - D - E should all get RAF, if they're similar level and grouped.
Even if A were a level 80, B will qualify for RAF due to meeting conditions with C.