BTT_OPENED_URL_FROM_URL

Not sure if this is possible, but it would be handdy to be able to select
url actions based on the originating url root domain, such as links clicked from google would be BTT_OPENED_URL_FROM_URL == "google.com"

Reason im wanting this is i use slidepad with each tab having its own relevant browser. at the moment i cant see any way of identifying the seperate tabs in BTT.