Variable expansion question

I'm trying to..
  a) modularize/simplify my .procmailrc for my own sanity
  b) make it generic enough that others can use it by
     changing two variable declarations
  The two declarations are (I think<g>)...
MYISP="(interlog\.com|interlog\.net)"
MYLISTS="(procmail|risks@)"
  Are there any special rules about special characters.  I.e. do
backslashes have to be doubled up and parentheses and pipe-signs
require leading backslashes ?

-- 
Walter Dnes (Toronto)
<waltdnes(_at_)interlog(_dot_)com>