Sort order, return the first 20 results, and the last 80 results

[Michael Tracey]

Hey all,  I'm interested returning 100 rows in a query, with a sort order on a 
tfloat field, but return the first 20 results, then the last 80 results.  I'd 
like to do this without two requests, to keep down requests per second.   Is 
there any way to do this in one query with function queries or another method?

Thanks, Michael