I think the best option would to create a group Distribution List email group and add everyone to that group that should receive the subscription and then subscribe that dlist to the desired report. Check out this knowledge base article for the workaround: Unable to Add Subscriptions for Multiple Users | Tableau Software
Additionally, it looks like someone has submitted this idea to the Idea Forum: Use Administrator account to subscribe users to emails To add your weight to the request, vote on the idea! Tableau uses the Ideas Forum to determine what features and enhancements are in the most demand.
Thanks and hope this helps!