Filtering on two headers / checking MX entries ?

  Is there any way to filter on two headers at once?
  I want a rule equivalant to a procmal recipie like:
  :0
  * ^X-DSPAM-Probability: 0\.[01]
  * ^X-DSPAM-Confidence: 0.\[89]
  # Deliver to inbox without confirmation.

  Is there any way to express this with TMDA's filter spec?

  Or is the best way to do this by adding a single custom header with 
procmail, then looking for that in TMDA?

  In procmail: 
  :0f
  * ^X-DSPAM-Probability: 0\.[01]
  * ^X-DSPAM-Confidence: 1|(0\.[89])
  | formail -I "X-CRH-OK: Yes"

  In tmda:
  headers '^X-CRH-OK: Yes$' ok

  Also, does anybody know of a way to check if the origin of an email (as 
determined by the earliest of the Received headers) is actually an MX?
  I'd like to avoid sending confirm messages based on email from machines that 
weren't MXes.

thanks,
crh

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.6 (Darwin)

iD8DBQFFkquNWBjzOA9cliERAtQLAJ9eTNv6H3HaEnpLvYHOLeBgleDUxQCdFUmE
GOOgQRjHdeI1uOsC+cUZ6sI=
=M9L5
-----END PGP SIGNATURE-----