Outlooks duplicates messages with rules

Hi,

Im trying to create a set of rules that filters out an inbox into a set of sub folders. Although, for some bizzare reason outlook seems to be duplicating emails...
for example:

Rule 1= when email arrives and If subject = A or B, MOVE email to Folder X.
Rule 2= when email arrives and if subject = C or D, MOVE email to folder Y.
Thus if an email arrives with subject A,C its copied to both folders X & Y.

I dont want this. I want some sort of order of precedence whereby Rule 1 is executed before rule 2- and if it checks out to be true then the email is MOVED to X. thus rule 2 has no email to take action upon, and thus it is ignored and no duplicates are created.

I tried to set the order the rules are executed in in the rule settings window, but this seems to make no real difference.

Is there an option to fix this, a patch? anything?
a 3rd party component?

thanks