By signing the agreement, you gave your word that you would follow it to the letter and intent. If you wish to do something other than live up to your end of the agreement, you need to contact the people you made the agreement with and work with them to renegotiate that agreement.
You're asking the wrong question. You should have asked last week, or the week before, or whenever you signed this agreement. And your question should have been: "Should I sign this agreement which restricts my publication rights of my article?"
I don't see that there is any question at this stage in the game. You've got a contract, and you are legally (and morally, in my opinion) bound to uphold it.
Sorry to be so blunt, but the issue isn't really debatable on the grounds of "I think I've found a loophole". Even if you had, the intent of the agreement was clear...good faith suggests you should follow it even if there is a loophole.
And that's all I have to say about that.