Your musician friends moving to the San Francisco Bay area may want to know about this group:
http://www.ccwindsymphony.org/About.htm
The conductor is very fine, has a PhD from University of Michigan, and played in the Fifth Army Band.
Other groups worthy of consideration include:
http://www.windband.org/foothill/
and,
http://www.walnutcreekband.org/
There are many other bands in the greater SF Bay area. I'm sure your friends will find something to their liking.