Persist only specific IPs destined for a VS

I believe that this is the general iRule structure that you will probably need, but I'm not sure exactly what you are looking for with the description that you have given, so I have included other options that are commented out.

You can find specific information on the perisit option used here:

http://devcentral.f5.com/wiki/default.aspx/iRules/persist.html

 
when CLIENT_ACCEPTED {
if { ([matchclass [IP::remote_addr] equals $::TestDataGroup ]) } {
persist cookie insert
Specific Pool
pool Your.Pool.Name
Specific Pool and Specific Pool Member
pool Your.Pool.Name member 10.10.10.10 80
}
}

If you are going to use a matchclass you might want to read SMP and Hoolio's thread about the differences between v9 matchclass and v10 class match:

Thread Name: v9 matchclass and v10 class match iRule commands

http://devcentral.f5.com/Community/GroupDetails/tabid/1082223/asg/50/afv/topic/aft/1172225/aff/5/showtab/groupforums/Default.aspx