I endorse Bob Cox's letter in the recent MAAM. I think either a Sierra Vista or All-Arizona RG is an excellent idea. When LA held their RG up in Ventura a few years back, it informally became a joint LA-CIM RG. (BTW, the chair was Carole Young, who went on to become the first person to chair two RGs in a single year, for two different groups.) It benefited both groups, as it did when we repeated in Oxnard a couple years later/ago. I'm all for joint RGs. At one time I even came up with a possible theme for an Arizona RG -- The Wizard of AZ. Of course, we would have to get Bob Cox out of that feathered hat of his and into a wizard's hat, but if we put feathers on it maybe it could be done.
(Channel Islands Mensa, CA)