So a similar thing has been asked before at least once.
Yet doesn’t mean it is a good setup to allow for multiple dynamic IP ranges in same subnet.
Similar effect can be created by splitting using reservations (although you need to explicitly define them).
Windows also support superscopes.
In any case, dnsmasq seems to limit us in various ways (also very restricted DNS) and I wonder if it should be scrapped for something richer in NS8.