Multi Domain Configuration Filtering Search Results

We have a multi domain site, same basic site and content, but broken up into three regions, ie: us.example.com, asia.example.com and europe.example.com. There are three page nodes on the root, US, ASIA and EUROPE. Each domain has it's home page set to it's respective node.  Config details for multi domain sites can be found here. My question relates to search filtering, I have gone thru all the examples I can find, some will do part of what I want.

In a nut shell, what I need to do is depending upon the domain that is being accessed(US, ASIA, EUROPE) I want to exclude page results from below the other domain page nodes (ie: if I am accessing us.example.com, I do not want page results from below the ASIA or EUROPE nodes to display).

It is pretty straight forward to create a custom search result widget, but I have not found a way to filter the results, I've found a code snippet that is just a class file here, this appears to give me the start of what I want, but I am unable to get this class file in a state that will allow me to use it as a widget or incorporate it into one of the custom search result widgets I have created. When I try to incorporate the class code into a widget, specifically the initializecontrols routine. I've read so many articles and posts I now have myself completeley confused.

If I could just get the class solution to work, I think I could modify it to my needs, but because the example uses thunder, which I can not setup properly because of the multi domain configuration. I'm at a loss on how to continue.

If anyone can explain or point me to a post or article on how to register this class against the search results widget without thunder it would be greatly appreciated.

Thank you

Hi John,

Thank you for using Sitefinity CMS.
Our built in search widget works with already generated search index(Administration -> Search indexes), these indexes are by site. So you should have for example (IndexRegionUS, IndexRegionEurope, IndexregionAsia). So the search results should find content for the specific site. If this does not work for your case, please send more detailed information about the content and the providers you are using.

Regards,
Strahil Strahilov
Telerik