Thanks Ashley, i was a bit confused with globals and locals - though local you mean Instance Varibale. It's clear now.
No, instance variables are added in the properties bar. Try dragging a global variable block in to a group of events. It turns in to a local variable block.
ne more thing for you to consider - adding "Toggle Active on start" to contex menu after pressing RMB on group block
There's "Toggle disabled", does that do what you want?