You can start your meeting with an agenda and achieve the same effect. What you are describing is an institutional problem requiring an institutional solution:

You can start your meeting with an agenda and achieve the same effect. What you are describing is an institutional problem requiring an institutional solution: the people organising meetings need better training on what it is they're trying to accomplish. Update your meeting invites with an agenda. No agenda? No meeting. It's pretty straightforward, and you don't have to assign people into 16 or 81 pseudo categories to trick them into paying attention to a meeting that didn't need to happen in the first place.