no, this is not true. And is an issue with TNDL
All link-16 donated tracks contribute to MSI regardless of source(which that part is true, we don't have this part of MSI yet). Link-16 itself is limited in bandwidth so it cant support everybody donating to everyone at the same time. It's the reason why the DONOR list exists, so you can allocate track donation bandwidth to relevant aircraft. C2's donate to everyone per its Jset, F/F's have to be opt in.