Create a new course Add an ‘External Tool’ activity to the new course and configure it: Use an arbitrary Tool-URL (does not have to exist) Add line “mygroups=$Moodle.Person.userGroupIds” to the custom parameters field (you might have to unfold the form to see the custom parameters field) Save and return to the course Click the ‘External Tool’ activity and capture the network traffic of your browser. The “launch.php?.. “ contains a from with name “ltiLaunchForm” that should contain the following two hidden fields: <input type="hidden" name="custom_mygroups" value=""/> Now add two groups to your course and add yourself to the first group. Again click the ‘External Tool’ activity and capture the network traffic of your browser. The “launch.php?.. “ contains a from with name “ltiLaunchForm” that should now contain the following two hidden fields: <input type="hidden" name="custom_mygroups" value="1234"/> whereas 1234 should be the id of your first group Add yourself to the second group Again click the ‘External Tool’ activity and capture the network traffic of your browser. The “launch.php?.. “ contains a from with name “ltiLaunchForm” that should now contain the following two hidden fields: <input type="hidden" name="custom_mygroups" value="1234,1235"/> whereas 1234,1235 should be the two group-ids