can we direct traffic based on their cookie to a particular server using iRules

I aint good at Irule 🙂 But logic would be like this I believe,

when HTTP_REQUEST {
        set DEBUG 0
        set PDC_OpenAM_pool ""PDC_OpenAM_pool""
        set SDC_OpenAM_pool ""SDC_OpenAM_pool""
        if { [HTTP::cookie exists ""amlbcookie""] } 
            {
            if { [HTTP::cookie value ""amlbcookie""] equals ""01"" } 
                {
                if { $DEBUG } { log local0. ""CLIENT IP is [IP::client_addr] $PDC_OpenAM_pool selected"" }
                pool $PDC_OpenAM_pool
                } 
            elseif {[HTTP::cookie value ""amlbcookie""] equals ""03"" } 
                {
                if { $DEBUG } { log local0. ""CLIENT IP is [IP::client_addr] $SDC_OpenAM_pool selected"" }
                pool $SDC_OpenAM_pool
                }
            }
                  }

You can also use active_members logic to control redundancy.