RFE? Or is there an easy way to do this?

[Linda Walsh]

I have some email accounts that I use with particular vendors or lists.  I have 
a few email accounts only known to a single person or company. 

What I'd like to do is someway of white-listing a "to-addr" if it is from a list 
of "from-addrs"....else add something (constant?) to its spam score.

An even more advanced but non-trivial check would be "if to addr(X), and not in 
my contacts(addr-book), then SPAM, else ok....

Anyone else have their ways to do these checks?

thanks,
-linda