Adding subscribers to Groups

We’ve been using Mailchimp for WP for awhile, successfully adding our WooCommerce customers to multiple lists..however we are in the process of combining all our lists into a single list with groups and I can’t see to add a user to the groups underneath the list. I ran an order through using my email address but I was not added to the two groups I wasn’t already a member of.

When I removed myself from the group I was already a member of and ran another order through, I don’t show up in any of the groups.

I would like anyone who places an order, or creates an account in our WooCommerce store (and checks the opt in) to be added to all three groups in our new list. How can I achieve that?

Thanks