The term combiners is what fans referred to the "special team" concept ever since they were released in 1985. No kid our age at the time knew of the word "gestalt" and I still don't use it, as it sounds too cerebral for a kid's toyline. So we (my friends and I from way back in 1987, up to the present), would refer to any multi-member group that "combines" as "combiners".
The introduction of the four new teams in the UK Marvel story "Second Generation" would keep highlighting the word "Combine" when each team combined... making it the key concept/gimmick to refer to with multi-member combining teams.
Soundwave even describes them as "Combining Transformers" in Issue 64. Devastator was also referred to as "combined" in the US Marvel Comic.
Even the catalogues from 1986 and 1987 describe those mult-member groups as being able to "combine" or "join"... since "combiner" made more grammatical sense than "joiner" to us youngens of that time, I have never seen the term questioned or disputed on any fan-forum or ATT (the first online community) before this was brought up here.
Trying to convince the fandom that they are wrong in using the universally designated term by fans for the last 25 years is a big challenge.
Even the semi-official term "Special Teams" didn't take hold within the fandom, despite it being used a fair bit (briefly) by the UK Marvel team (Issue 54, 63, 64)... since it sounded lame, made them sound retarded, it was quickly dropped.