Nextcloud version (eg, 12.0.2): 18.0
Operating system and version (eg, Ubuntu 17.04): Ubuntu 18.04
Apache or nginx version (eg, Apache 2.4.25): 2.4.29
PHP version (eg, 7.1): 7.4.2
The issue you are facing:
How can I make users see the members of groups which they are member of?
As an administrator you can see it in the user management, but is there a way to let users see this for themselves? This way the user knows who his data is shared with when sharing with groups is done.