This may have (correct me if I'm wrong) been suggested in the past, if so I haven't seen it.
But pretty much - add Group SMS'ing.
It'd work just like a /SMS groupname message - if you have people in it added, they'd show up with names, if not - they'd show up as their numbers. Commands could be simple, like - /createsmsgroup name, /addsmsgroup person/number, /renamesmsgroup name, /removesmsgroup person/number.
This would discourage certain demographics being forced to use radio's and it's a lot more realistic than certain demographics having to do so (especially in this day and age, imo.)