Sometimes you need to speak to one person. Sometimes you need to reach a whole group. The difference should not be whether the message feels like it was meant for them.
Your relationship information already describes who is who. An audience is a view of that, not a list you maintain by hand.
One system, one contact record. Open anything below and keep going from there.
Audience communication works best when it is part of relationship building rather than message distribution. Same records, same history, same system.