[exim] how to skip rbl checking for whitelisted hosts

Hi,
I am running exim-4.63-5.el5_6.2 and I have created a whitelist hosts file:
/etc/exim/filters/whitelist-hosts

I want the RBL checking skipped if the sender hostname is in the whitelist file. Can someone tell me what to add to my
config file and where?

Here is the RBL snippet from my config file:
# Mark it White
warn dnslists = hostkarma.junkemailfilter.com=127.0.0.1
     set acl_c0 = white - dnswl - $sender_fullhost

# Mark it Yellow
warn dnslists = hostkarma.junkemailfilter.com=127.0.0.3
     set acl_c1 = yellow - $sender_fullhost
     message    = X-Warning: $sender_host_address is in a yellow list at $dnslist_domain

# Using the Black List
deny dnslists = hostkarma.junkemailfilter.com=127.0.0.2
     message    = X-Warning: $sender_host_address is in a black list at $dnslist_domain

# Other Blacklists
deny !dnslists = hostkarma.junkemailfilter.com=127.0.0.1,127.0.0.3
     dnslists = zen.spamhaus.org : dnsbl.sorbs.net
     message    = X-Warning: $sender_host_address is in a black list at $dnslist_domain

Thanks,
Kerry.