Hi.
to group events names, use a /
For example Player/Jump Player/Run
You can do this for variables as well.
I am not sure, but I believe the hard limit (1000) is from unity's Popup (EditorGUILayout.Popup) not Playmaker.
You have also Send Event By Name, but you need to make sure yourself that the names are correct.
But how come you got so many global events?
Maybe you should review your code setup, as I think performance wise this is not good as well to have that many global events.