[xwiki-users] groups: mailing them

I intend to make more use of groups and updating the members on changes relevant to them by sending them e-mail. Watchlists look too technical/difficult and forcing group members to use them is too cumbersome, so I'd like to start simple: exporting the mail addresses and mailing them the old-fashioned way. Now for the coding: I started with http://code.xwiki.org/xwiki/bin/view/Snippets/CsvExportOfUsersSnippet yet group membership is only enclosed in the objects of the respective group pages. Any suggestions how to either export only members of a set group, or include subscribed groups as a column? Thanks in advance!