I believe this is what I want to do? I'm not sure. I've made some illustrations and grouped all the components together, however when I want to resize them, the stroke stays the same? I think that's what's happening anyway. I've attached a picture of what's happening. Any help is appreciated thank you!
In the Transform panel, untick 'Scale Strokes and Effects' (if I understand you correctly).
Try if "scale strokes &effects" in Preferences > General already helps you. Must be acticated before scaling.
This worked thank you!