we build packages exclusively for i586 and x86_64:
and for these distributions:
I don’t know anyone who has installed EGroupware on a RasPI so far.
I would rather advise you to use a used NUC. You are much more flexible and have more power. That’s more fun!
But you can install EGroupware alternatively from Git or as Archive:
For the webserver (+PHP, …) and the database you have to take care of yourself. Maybe there are ready distributions for the RasPI for web applications?..
Maybe you will find someone who writes an installation script.