So really you're just looking for one long rule?
Physical Resist <= 12 AND Poison Resist <= 10 AND Exceptional AND Fire Resist <= 4 AND Cold Resist <= 4 AND Energy Resist <= 4
I dunno. Rules are very specific and very personal. It doesn't help that I have no idea about the imbuing thing.

And obviously you'll have to play with it alot even after you get more comfortable how the complex rules work.
Anyhow, you can vary the above if you want to add cases. Also, an omit rule can throw out things that are just too large or too small.