GTM Balance iRule

I have a three proxy servers that I need to balance between and maintain persistance.

 

172.20.37.3dix-bluecoat-01

 

172.20.5.3sho-bluecoat-01

 

172.20.5.6sho-bluecoat-01

 

I want the LDNS of DIX DNSservers 10.65.144.32, 10.65.144.33 10.65.146.32, 10.65.146.33

 

to use 172.20.37.3dix-bluecoat-01

 

I want the LDNS of SHO DNS servers10.64.144.32, 10.64.144.33

 

to use 172.20.5.3sho-bluecoat-01

 

I want the LDNS of SHO DNS servers 10.64.146.32, 10.64.146.33

 

to use 172.20.5.6sho-bluecoat-02

 

I have created the following GTM Pools

 

WEBPROXY_SENTRY_POOL_1-172.20.37.3dix-bluecoat-01

 

WEBPROXY_SENTRY_POOL_2 -172.20.5.3sho-bluecoat-01

 

WEBPROXY_SENTRY_POOL_3 -172.20.5.6sho-bluecoat-02

 

I was working on an irule like below for a solution but my GTM hates it can someone set me on the rght track>

 

when CLIENT_ACCEPTED { if {[class match [IP::remote_addr] equals 10.64.144.32 ] } { pool WEBPROXY_SENTRY_POOL_2 } elseif {[class match [IP::remote_addr] equals 10.64.146.32 ] } { pool WEBPROXY_SENTRY_POOL_3 else { WEBPROXY_SENTRY_POOL_1 } }