I understand that when "those" is referred to as the subject of the verb we use "whom", and when "they" is the object we use "who".
But consider the following sentence,
This is being funded by future taxpayers, many of whom are yet to be born.
Are 'they' the object of "are" (to be), in which case 'they' should be "who"? Or are 'they' the subject of some other verb? On first writing, "whom" seemed correct, but, on looking again, I think it should be "who" because I can't see what verb 'they' could be a subject of.
This was not answered here: Many of who or many of whom?
That question was wrongly marked as a duplicate (IMO) and not answered in the linked question (AFAICS). My question is essentially the same.