To resolve a chasm trap, you make separate queries and then combine the results. The best way to accomplish this is to define a context for each table at the many end of the joins. In our classroom example, you could define a context from CLIENT to SALE and from CLIENT to RENTAL.
When you run a query that includes objects from both contexts, this creates two SELECT statements that are synchronized at runtime in SAP BusinessObjects end user query tool to prevent the creation of a Cartesian product.