We have the same problem in our club (having more than 10 teams). People from other teams can volunteer as referee. But the coordination thereof is tedious.
It would be nice to be introduce the role of referee and enable the voluntary duty feature on it.

* The club admin can define a referee group, composed of club/team members.
* This referee group gets to see the schedule of all home games of all (or subset of) teams in the club.
* The feature of duties needs to be enabled on that referee group. Members can volunteer for a referee job on a selected game. Or club admins can assign referee duties. Preferably, referees can choose a game either on date (based on their personal availability that day) or on team. These duties have the nice notification mechanism built in.
* Some form of calender overview of referee assignments across all team would be very helpful for the coordinator (instead of having to inspect the games of all teams one by one every weekend)

Love this idea. I think a good way to implement it would be to make it possible to assign anybody from within the club to tasks for games. That way one could create a "team" of referees / umpires as well as using individual members of other teams for specific duties (e.g. scoring table etc).

If the ref title can be renamed as Umpire according to the sport that would be good, also The ref type can be modified as ref/umpire or Umpire Coach that would be helpful as we often have an Umpire coach for junior umpires

Agree but need to allow for other sports where different ref/umpire combinations apply