When viewing search results, group membership is only attributed to the main contact. Extend it to all its members.
In the "groups" tab insert a second column in which you can see, at a glance, who is part of each of them?
Implement exporting with groups.
Synchronize contacts with Mailchimp via API
11 freelancers are bidding on average €191 for this job
Additional features for Joomla Contacts component, Mailchimp integration Relevant Skills and Experience Joomla, PHP Proposed Milestones €155 EUR - Joomla/PHP programming