Is there way to define anchor point while defining class in FL5?

markClass [gravecomb acutecomb circumflexcomb] <anchor 0 500> @MARK_TOP_CENTER;

The example is above which is part of this. I can't seem to put all those in a single opentype feature as FL5 automatically breaks them apart into ccmp and mark features, and naturally markClass code at the start is thrown into whatever feature is above in the list.