Did you know you can "include" the contents of one event sheet in another? This plus groups is hands-down the way to go. My game has a huge amount of "global" code that handles basic things like controls, dialogue box logic, how loading zones work, etc, and then I include that master sheet in every other sheet for the individual levels so I don't have to deal with that stuff at all unless there's a problem with it. Putting things into groups shouldn't mess them up per se, as long as the groups are Active in the way you'd want, but do look into whether you messed up the order of some events by moving them into groups? Make sure Construct can cycle through all the events in order and in a way that works.