Place boneless, skinless chicken breasts between 2 pieces of plastic wrap abd pound to 1/4 inch thickness.
Place chicken breasts on greased grill using medium-high heat, close lid and cook, turning once, a total of about 12 minutes or until no longer pink inside or meat thermometer inserted in each piece reads 165(74C).
On each chicken breast, slather some BBQ sauce on one side.
Place slices of ham on each breast. Close lid. Let heat for 1 minute then put a slice of cheese on each breast/ham piece. Take off grill.
In a bowl, combine well the mayonnaise, honey, horseradish and dry mustard, spread over cut sides or rolls.
Build sandwiches with chicken and garnishes.
Garnishes-Lettuce, Tomato, Thinly Sliced Onions, Sliced Pickled Hot Peppers.