Effect on number agreement when new numbers arise

Khangaþyagon verbs are marked for number of the subject (singular/plural).
The plural form is marked with a suffix in the last position, both for
nouns and for verbs. Wagoragon, as I have previously mentioned, has
developed a third number, the multiple, used when the quantity of things
referred to is, at least in principle, known. This is formed by
reduplication. It occurs to me that a new form of the verb should arise to
agree with subjects in the multiple. Any ideas what form it should take?

Pete