Adding real and virtual servers

I have 2 computer servers.
1 - WHS mail.biggdog.biz
2 - Linux sarah.biggdog.biz

1 =
Host - mail.biggdog.biz
plain HTTP
Port 80

2 =
Host - sarah.biggdog.biz
plain HTTP
Port 80

This looks like a problem already with the ports being the same. Is this correct?

Also I want to have people to be able to connect to sarah.biggdog.biz on a different port for different things.
sarah.biggdog.biz:9999
sarah.biggdog.biz:8899
now the tricky part "for me"
sarah.biggdog.biz is also http://photos.readynas.com/sarah
how can I make this work?

With this how should I set up my virtual web servers as well?