Since your earlier post indicates that you are hosting all 7 sites on the same virtual IP, and both servers are configured to answer for all 7 sites, you most likely don't need an iRule.
You can most likely simply create a single virtual server on the BIG-IP, and a single pool containing the 2 servers.
Assign the pool as a resource to the virtual server
If all connections from one client have to go to the same server, you will need to configure a persistence profile and apply it also as a resource to the virtual server.
Some monitors would probably also be in order to make sure the servers are healthy and ready to accept traffic. At the very least the default HTTP monitor should be applied. You have a number of other monitoring options, such as creating and applying a specific monitor for each website, requiring they all pass before the server can accept traffic.
Look for "pool", "persistence" and "monitors" in the LTM manual which may be found on http://tech.f5.com/ (
Click here)
HTH
/deb