Flyertalk does not have a forum for FZ but airlines like AA, BR etc have sub-headings where it is explained that AAdvantage, Infinity MileageLands etc include not just the main carrier behind the frequent program but also the main carrier's various subsidiaries/partners etc which also use the same frequent flyer program.

With regards to EK, FZ and Skywards, note:

i) FZ has no forum here and posts relating to it crop up here, in the Middle East forum, other Middle Eastern airlines forum and various other places;
ii) FZ and EK are both owned by the same entity - the Government of Dubai; and
iii) both FZ and EK use the same frequent flyer program - Skywards.

In fact the EK website even states:

"Emirates Skywards is the award-winning frequent flyer programme of Emirates Airline and flydubai, launched in May 2000. Membership of the programme provides access to a world of exclusive benefits designed to make travel more rewarding and enjoyable."

Would it not make sense to keep the main heading for this forum as is, but include a sub-heading explaining how it also includes FZ?

Something along the lines of:

Emirates l Skywards
Emirates Airline and flydubai