No, this is not possible and I have no plans to allow it right now. Did you have a use case in mind?
-The script runs, pulls out value in player's last post that has their attack, compares to enemy-boop done.
-hidden values that GM can sneak into character sheet generator can be revealed and compared to other values by characters.
Or a little miscellaneous.
- Player just has to put in a number in his/her post to assign certain place picture of another players character in a box int he box to show the characters have some sort of relationship.
I mean once we can pull values from other posts; we could pretty much make video games based on the forums code. It could spiral into some really unknown results.