Using gmail in the elementary classroom

I use gmail constantly to keep the parents of my second grade students informed.  I put all of the parents into my contacts list, but then, I also make up several groups of them.  I have an entire class group to which I send out my weekly updates; a group for only those students who will be making their First Eucharist/First Reconciliation (I teach in a Catholic school but only about half of my students are Catholic so only those parents need to know that specific information), and a "holiday party volunteers" group for which I make a google docs to which they can add their name by which item they want to send in for the parties, or for which party they want to volunteer.  I also have a faculty and staff group.