Yes of course, I wish provide for two small groups of people an application set ; each group can access to its application set with its specific domain name.
For example:
The group A use the domain aaa.com and the group B use the domain bbb.org , a person from a group can used his webmail (private or public) with the good domain name.
I don’t know exactly how can I do that, it’s may be possible to install two applications webmail for each domain (but at least one of application webmail must be public)
You can either install the webmail app on both domain and the webmail public for the bbb.org , so that the user don’t need to enter SSOwat login.
or
Copy the nginx config profile for webmail to the other domain. That way single app will server both the domain.
eg.
Roundcube is installed on mail.aaa.com , so you can go to /etc/nginx/conf.d/mail.aaa.com.d/ , copy the roundcube.conf and paste it in /etc/nginx/conf.d/mail.bbb.org.d/. This way both mail.aaa.com and mail.bbb.org will server roundcube.This would not work for all apps,but I think it will work for roundcube. I tried it long time back.