Policy to not show every groups and contacts

[mario-spitze]

Is your feature request related to a problem? Please describe.

We would like to use auto completion within internal groups. Our organization have a lot of groups with external contacts, too. If we activate the auto completion, like in #3964, to many people see to many other contacts with private mail address. To simply limit the space all external accounts collected in one group. Nextcloud sync this group and all external contacts see the private mail address from each other in the corresponding contact list.

Describe the solution you'd like

Filter groups with the availability to use the auto completion and the automatically created contactlists.

Describe alternatives you've considered

No response

Additional context

Users and groups are defined in LDAP directory.