excluding patterns from the --delete option?

[Mason Lee]

   Please could someone tell me if it is possible to specify in a single 
rsync command that the --delete option should apply to all files except 
those matching a certain pattern?  I want to do a -a archive, except 
that a few directories should not have --delete applied.  Do I need to 
use two rsync commands to achieve this?

   Thanks in advance for any help!

___
Mason Lee
Berkeley, CA