Do you think getting the presidents of each GLO together to attend a meeting with Jones telling how much they like and admire Mary would do any good? If nothing else, I would have every chapter at Iowa write an individual letter to Mary showing your support and letting her know that you don't agree with her reassignment. Having things in writing is always more powerful than saying them verbally.
Also, send an editorial letter to the school paper and the town newspaper voicing your strong objection to her reassignment and give examples of her fair and ethical treatment of the Greek System in the past. Throw the bad press back in Jones' face by focusing it on him instead of the Greeks.
Just a suggestion!
I really hate that all this is happening to y'all.