direct request traffic to the specific directory of another server

String map won't work for my case because I do not have unique string to map for the IF and Elseif statements. Also the pages that I want to show to users are at specific directory of the servers 10.10.10.1:9290/las, 10.10.10.1:9290/thredds and 10.10.10.1:9280/las.