Websense implementations use both the "url-server" command AND the "filter" command. The former defines the server to send the requests to, the latter defines which local and/or remote IP addresses are subject to the filtering.
The command ref is here:
http://www.cisco.com/univercd/cc/td/doc/product/multisec/asa_sw/v_7_2/cmd_ref/ef_711.htm#wp1762232
You will probably already have a command of the type:
filter url 80 0 0 0 0
so use the "except" option and enter another command to exclude one particular source (local) address from being checked. You'll end up with something like:
filter url 80 0 0 0 0
filter url except 10.1.1.1 255.255.255.255 0 0
which will exclude 10.1.1.1 from being checked.
