Hi there. Thanks for the great question.You are correct. s2Member does NOT have this feature built-in yet. MailPress would perhaps be an alternative for now, or one of the solutions that I listed above.
Yes, this feature is coming soon, most likely after work is completed on the improvements to Custom Fields, which we are also VERY close to finishing. Perhaps somewhere around s2Member v3.2.8 ( middle of November - maybe sooner ).
and if it will be possible to select certain members on criteria like the value of a certain custom field
This was NOT on our TODO list, but I'm adding it now.
@TODO :: additional filtering to be added after Custom Field improvements and internal mailing lists.Thanks for the great suggestion.