MiRai has already covered it but...

A > B > C
A > D > E

Let's say A is level 85.
And BCDE are all level 20.

The RAF links from A > B and from A > D, will both be invalid.
Because A is 65 levels above them.

However, B > C and D > E are valid RAF links.
Which means they get RAF experience, even when grouped with A.