Need assistance with multiple Plex servers behind SSG-5

Relatively new to Juniper SSG-5.  I am trying to setup multiple Plex servers that will use different external ports, but use the same internal port.  so let's say it looks like:

PlexSrv1 - 192.168.0.23 port 32400 - working

PlexSrv2 - 192.168.0.24 port 32410 - not working

PlexSrv3 - 192.168.0.25 port 32420 - not working

I have external access on 32400 directed to 192.168.0.23 which is working.

I need to add external access on 32410 directed to 192.168.0.24 port 32400

I need to add external access on 32420 directed to 192.168.0.25 port 32400

I'm certain it's easy, I'm just not sure how to do it.