Hello & welcome,
first of all sorry for my bad english
For your problem go to the instrument section and there (from the manual)...
Exclusive class
This parameter can define one or more exclusive classes, by assigning to a set of divisions within a class the same parameter value other than 0. When an exclusive class is defined, any note triggered from one of the divisions of the exclusive class ends all the other sounds of the same class. The scope of an exclusive class is the preset in which the class is defined (a sound triggered in an instrument will end a sound of another instrument if the two instruments are in the same preset). This effect can be used for percussion instruments like a cymbal. Basically playing one note automatically terminates another in the same group.
Enjoy