Unfortunately, global groups are designed to be used with Global Objects. They will not work with non-global objects. Object Groups containing Text Objects no longer selectable for Shadow Events if made Global - #9 by Silver-Streak
From an optimization standpoint, however, I believe you can reuse events/use external event sheets/etc that target a Non-global group, so long as you have a group with the same name in the scene it is being used in. It will mean you’ll need to recreate the group in every scene you need it in, but it will allow you to exclude it from scenes you don’t want to use it, as well as allow you to exclude objects from the scene that you don’t need.