Hi,
to avoid all internal groups or groups without email showing in the address book browser, you may want to follow these steps:
sudo mkdir /etc/zentyal/stubs/zarafa (in case directory doesn't exist yet)
sudo cp ldap.openldap.cfg.mas /etc/zentyal/stubs/zarafa
Then edit /etc/zentyal/stubs/zarafa/ldap.openldap.cfg.mas and alter line with ldap_group_search_filter to this:
ldap_group_search_filter = (&(objectClass=zentyalDistributionGroup)(mail=*)(!(internal=1)))
Restart zarafa services & re-create the config files from you modified template:
sudo /etc/init.d/zentyal zarafa restart
to make the changes become effective
This will result in a much cleaner view of the Global Address Book picker in Zarafa Webapp.