http headers

Noted...What if my VIP .77 already has a two web servers .78/.79 hosting one sharepoint service. Now our same customer wants to use .77 as the virtual server and add two more servers .80/.81. On .80/.81 they want to host 7 websites maybe more. Since they want to use the same virtual server shouldn't there be an irule? I am really new at this so please bare with me. It would be great if this customer had a new ip for their virtual server. The problem is IP's are limited. Maybe this will help a bit more and hopefully someone can point me in the right direction if you haven't already.