[Exim] condition for spamcheck router

hello,

I'm trying to work out what I should use for a condition statement in my
spamassassin router, that will not check the email if:

a) it isn't already flagged as spam
b) it isn't already scanned
c) it wasn't sent either locally or from a host we relay for

Could someone help me out with this? Any help would be much appreciated!


cheers, Michael