Snapping should have the option to work with all the objects regardless if they are grouped or not and even within different groups.
If I understand you correctly, this would be like snapping to objects as if they weren’t grouped, is that so?
This, however, I’m not sure I understand. Could you elaborate? Perhaps provide an example, or a demo of another app that does that you’re suggesting?
I guess treating all the element as ungrouped should work.
See the gif: Having two groups (for two cards, for instance) the violet background doesn’t snap to the size of the blue one, so you need to add guides (which don’t snap to grouped items) or ungroup the cards like in the sample below.
In Figma that works but the oposite happens: sometimes you need to snap only within the group in orden to have too many non related snapping points. That’s why I think that should be a toggle option: to snap to all elements or not.