plural possessive form of a mutated plural?

Here are two examples of mutated plurals: more than one goose= geese; more than one man= men

1)Say you had 2 or more groups of geese. I.e. group #1= African geese & group #2=buff geese. If you wanted to associate these groups together but still observe the fact that they are different types of geese, would you say geeses? (Buff geese + African geese = geeses) Taking this one step further, if these two distinct groups of geese share in the possession of something, would geeses' be correct? Say, one type of illness is common to two sorts of geese. [illness common to Buff geese(=Buff geese's illness) + the same illness is common to African geese(=African geese's illness) --> geeses' illness? ]

2)Say you had 2 or more groups of men: men from France(Frenchmen), men from England (Englishmen), and men from Ireland (Irishmen). Let's say you want to refer to the "European charm" that these groups of men have in common while still noting that there ARE different and distinct groups of men involved(i.e. different people groups--> peoples). Would you say the mens' charm?

I guess I'm just curious if you can make the sum of multiple groups possessive while keeping a distinction between these groups intact. (distinct GROUPS with similar possession)

Solution 1:

In terms of 'correct' usage, it's wrong to do what the OP is suggesting. Neither written English nor its spoken form has an accepted mechanism for making "the sum of multiple groups possessive while keeping a distinction between these groups intact" by inflection. Joint possession by multiple groups of the same type can be expressed, of course - but it is done analytically rather than by inflection.

1) You can say, 'an illness of both buff and African geese', or, 'a buff and African geese's illness', or a couple of other similar phrasings. The best choice of phrasing will depends on context.

Writing "Geeses" or "geeses's" in ANY context would mark the author as either a learner, or hopelessly illiterate.

2) You'd have to say something like 'the charm of all these men', or 'those men's charm' ... while doing what you can to remove ambiguity.

However, in very informal and colloquial oral conversations only, some native speakers DO use these kinds of 'recursive' plurals and possessives, ... but always with the awareness that it's 'bad English'. For example, someone might say, "Chimps and humans are two different specieses.Both specieses's behaviours are complex." ... but only for humorous effect.

Solution 2:

Yes, you can "make the sum of multiple groups possessive while keeping a distinction between these groups intact" - you just have to use a few more words to ensure the distinction. Your question already contains the answer: the "illness is common to two sorts of geese". If you're really keen to use the possessive, you could say "the Buff and African geese's illnesses" or "the Buff geese's and African geese's illnesses." Similarly, you could say "the French and English men's charm" or for greater clarity, "Frenchmen and Englishmen share a common European charm".

In all cases, the only time it would be grammatically correct to add an "s" to an already plural word would be if you're treating the word as a single item for counting purposes, e.g. "there are three geeses in that sentence." Even so, this would be an awkward usage and would be better rephrased to avoid the plural plural, viz. "the word 'geese' is used three times."