The rule in the title appears in Naffatun, Ghulam and Khawarij in RTS. In my city we've interpreting the rule as if every of the three units just mentioned were Ghulams, includin the Khawarij with Haris option. I've got some doubts abouts this, Where can I find more info about this?
If you're asking if you can form a Ghulam fireteam: Haris, then no, as it's not listed as a valid fireteam in RTF. If you're asking if the NCO Khawarij can join a Ghulam fireteam: Core, then yes it can.
This is the list of fireteams you can form in Ramah: http://infinitythewiki.com/en/List_of_Fireteams#Ramah_Taskforce Ghulam can only form a Core. This can include any combination of Ghulam, Naffatun, Khawarij, and possibly other wildcards. There’s no requirement to include even a single real Ghulam. However, as Ghulam can’t form a Haris, you can’t use the Khawarij Haris to make a “Ghulam” Haris. It has to be a Khawarij Haris, and is then limited to troops that can join Khawarij fireteams.
I wish we could do that...Khawarij NCO with a Ghulam Doc+ and Ghulam HMG...backed up with a double ghulam sniper, Naffatun HFT, Leila, NCO Grenade Launcher ghulam core...
The downside of the new flexible fireteams is that it takes more work to learn what the legal teams are. Basic teams requiring all the same troops is much easier to remember.
Well, they are slightly more confusing, but if you think of fireteams as of entities that you create empty, but already described as "unit X fireteam" or "special fireteam Y" with 2-5 empty slots that can be then filled with units that fit into those slots (by being/counting as X or whatever Y consists of, including wildcards that basically count as anything), they suddenly not all that different regardless of how inclusive they are. Of course, it's worth remembering that non-Core fireteams require some folks with Fireteam skills included into them by the time you finalize those fireteams, but that was always the case. Triads are a bit different still, and I don't remember how those fancy Greek fireteams work, but you get the point.