I have four teams in Operations. Alphas, Betas, Deltas and Gammas.
Each team has a sync with the same JSM project. e.g. Alphas sync with Project 1, Betas sync with Project 1, Deltas sync with Project 1, Gammas sync with Project 1.
Each sync was created by the team.
Each sync has a note rule to add a note on the alert when a comment is added to the incident.
When a comment is added to the incident, four (4) notes are added to the alert. Looking at the activity log shows that each sync's "Add note to alert" rule was executed.
Documentation here is not clear on this. My interpretation is that syncs could be instance-wide or team-based. I would not expect the rules in one team's sync to execute on the rules of another team's sync.
I am on JSM premium.