This is a two-part iApp - a single server and multiple pools.
If you want to have a single Virtual Server on which there are multiple pools configured based on the HTTP Host: header then you create an iApp using the prw.host-routing-virtual-server.
You then configure multiple prw.host-routing-pool iApps connected to the Virtual Server.
Cookie Persistence must be licensed
A VS must be configured otherwise Pool iApp creation ends badly