import Joomla users

I recently purchased RSMail
In the import I can select a Joomla user group which works fine.
However I need an extra filter since I regularly have to mail all Joomla registered users who have not checked in since date xxxx-xx-xx. More datefilters would be nice.
While importing als the namefields of the user (not only the log-in name) IP and the filtered date should be taken in; for all sake why not all essential fields of the standard Joomla userrecord.

Any further filtering could take place in the subscribers list.