To solve the problem of the unruly Mifflin Street Block Party, Mayor Paul Soglin is turning to an unlikely source: the rabble-rousers themselves. Soglin has asked students to work with city officials to tame the annual drunk-fest ? which turned especially ugly last year. A committee is meeting once a week to develop a plan for the end-of-the-school-year party on May 5. Their deadline is mid-March.