Formerly available only in EndNote Web, from version X9 onwards (currently EndNote 21) group sharing is now available through the EndNote desktop interface (still requires an online EndNote account). The other users will also require an EndNote online account.
If the user is not a student or staff member of Federation University, they can create a free online account at https://access.clarivate.com/login?app=endnote to use the online version of EndNote - some limits apply when using a free account rather than a sync account.
1. Create an online account for sync.
2. Click once on the group to select and highlight it in the EndNote groups panel.
3. Groups menu > Share Group
4. Add the emails of other EndNote users who can view your group (use the email address they have used for their online EndNote account, e.g. for syncing/backing up their EndNote library), and set the permission level for the invited users (Read Only or Read & Write).