Mail & iCal: Smart Folders and Smart Groups

I'm trying to create a smart folder in Apple Mail to list all mail to and from a Smart Group in iCal. However the Smart Folder doesn't show any e-mails that should appear in it...until...

...I add a another criteria that selects on a criteria that doesn't rely on a Smart Group - e.g., message contains the word "the".

Then all qualifying e-mails appear in the Smart Group, not just the ones that met the last qualifier I added.

e.g., Smart Folder "Cricket" looks for e-mails from Smart Groups "Cricket Team A" and "Cricket Team B". No e-mail appear now.
Then I add "Entire Message" contains the work "the". Then I see messages from Teams A & B in the "Cricket" folder.

Has anyone had this problem?