As a GSA administrator, you have control over the GSA’s user-agent string. Even though it’s generally not a good idea to rely on user-agent sniffing for content delivery, in this case you’re the one with control over how the client (your GSA) identifies itself. As such, if you assign a unique user-agent to your GSA, you can then sniff for it server-side and omit only the bits of content you don’t want the GSA to see.

For example, if you assign the user-agent “businessname-searchappliance”, you can use this php to omit content:
if ( !strstr($_SERVER['HTTP_USER_AGENT'], ‘businessname-searchappliance’) ){
// Content to omit goes in this block
}