See: What is Family Sharing? - What is Family Sharing? - Apple Support - "With Family Sharing, you and up to five other family members can share access to amazing Apple services..."
There is no workaround. You can set up two families but people can only belong to one family at a time so there won't be any sharing between the two groups. Apple also limits how frequently you can change families so it isn't really practical to jump between families. The wording is a bit ambiguous but the effect is the same:
Set up Family Sharing - Apple Support
"Remember, you can only join one family at a time, and you can only switch to a different family group once per year." June 2021
Legal - Apple Media Services - Apple
D. "Family Sharing Rules: You can only belong to one Family at a time, and may join any Family no more than twice per year. You can change the Apple ID you associate with a Family no more than once every 90 days. All Family members must share the same Home Country."