How to generate group unsubscribe link
I know I asked this question quite some time ago, but I thought I'd share the solution we landed on.

We found and tested two solutions that worked well. The first was using Tags:


Allow users to manage their tags
Create tags for the groups members can opt-in/out of
Create smart groups based on the membership status and tags
Sync the Google Group to the smart group for the associated tag


The second approach was very similar, but instead of using tags, we used a set of custom fields as checkboxes for each of the groups. We settled on this approach, because it allowed us more control over what was shown to the user and freed up tags for other uses.