Sessions and Rollback Segments

Hello,

   I have a large (about 800Gb) Database running in Oracle 7.2.2 on Solaris with various people running ad hoc queries, batch jobs, etc. during various times. of the day. Occasionally, somebody will run a job which will cause a rollback segment to fill up to the point where other jobs cannot run properly. I used to solve the problem by killing all the non critical sessions, and then the job hitting the rollback segment would be dead. Then I could then shrink the rollback segment by hand. Now that does not work, because the job is not being run by one of these "non critical" session. I want to know which session I need to kill to free this rollback segment. Does anybody know how to associate a session with a particular rollback segment? I would be willing to buy some product that will do it for me.

                        Thanks,
			Bill Eggers
			beggers_at_efit.elcm.eds.com