Group flats
Each of the answer words or phrases is related to a member of a well-known group in the manner of a specified flat type. The original example in January 1995 by ΧΕΙΡΩΝ is a transaddition group (6, 5, 6, 6): kobold, pilot, ersatz, swathe, based on blood, toil, tears, sweat (from the Churchill speech). Kobold is a “transaddition” (a transposal with a letter added) of blood; pilot is a transaddition of toil; and so on.
Tagging for group members need not be as detailed as for the answers (for example, “some group members are non-MW usage”). If the group members normally occur in a specific order, the answers must be listed in that order. The group should be a complete set; “copper, silver, gold” is fine, but three random elements would not be allowed.
Many flat types have been used in group flats. For example: the transdeletion group (shot, troops, Masai: transdeletions of Athos, Porthos, and Aramis, the Three Musketeers); the consonantcy group (forest, ascend, thread, frothy: consonantcies of first, second, third, and fourth); and the reversed consonantcy group (dory, thaw, alibi: reversed consonantcies of red, white, and blue). A homonym group base could also be used as a homoconcominym (which see). As with charade variants, inverses of flat types can also be used. A transaddition group (see above) is one possibility; others include addition, enheadment, or entailment. For example:
Solution: done, René, mine, fane, sone, lane, tine; the group is do, re, mi, fa, so, la, ti, clued by “chants”. In this flat, the seven cuewords are used in the verse in order, and each added bigram is the same. Neither of these is a requirement, but this is the sort of extra structure that makes a flat more accessible and more impressive.
You needn’t include the group words on your solution list (in the first example above, you need send only “kobold, pilot, ersatz, swathe”); in fact, it’s possible to solve all the parts of a group flat without ever realizing what the group is. In general, though, it’s best to include the group if you can, since it may help you get credit for an unintended answer.
The verse should include some sort of oblique clue to the group (for example, a flat built on Curly, Larry, and Moe might include the word stooges), but too direct a clue may make the flat too easy.