SET EXPLAIN / SQL

Using 4GL/SQL, is there a way to 1) obtain SET EXPLAIN output without executing the query and 2) accessing that output in order to conditionally run the query We have a very flexible way for users to create queries (sort of like construct, but more powerful.) The price, of course, is that they could create a resource intensive query that may not be desired (we have 400 users.) If we could parse the cost or indexing strategy we could determine when a heavy query has been requested, and protect our system from running too many of these at a time. We have Dynamic Server 7.3 (UC3-1) and 4GL 6.05 (we just got 4GL 7.2 but have not installed it) Thanks in advance for any response..... Dave Killough