(a) A person commits the crime of failure of a disorderly person to disperse if he participates with five or more other persons in a course of disorderly conduct likely to cause substantial harm or serious inconvenience, annoyance or alarm, and intentionally refuses or fails to disperse when ordered to do so by a peace officer or other public servant lawfully engaged in executing or enforcing the law.
(b) Failure of a disorderly person to disperse is a Class B misdemeanor.