Access to Optimizer results

We are using version 7.2 on HP-UX 10.10, and would like to know if there is any way to access to "cost" (from the optimizer) of a query while the query is executing without having the explain plan written out to a dataset. We are trying to develop a quey govenor that can be used to detect potentially long running queries and cancel them (so they can be run at a better time) before flooding the system.