TOP N in Reporting Services

Recently I moved from Crystal reports to the Reporting Services
module. In Crystal, I was able to use the TOP N function to report
only the top 15 customers in a particular query, and aggregate the
rest of the customers into an "All Others" category.

With reporting services, I've created teh same top 15 using TOP N in
the filter tab in reporting services - however, I'm unable to find an
easy way to aggregate the rest into the "All Others" bucket. I
believe this functionality exists without having to build a set of
subqueries -- can anyone help??

Thanks,