The part about playing house made me think of the WWII incident known as "Pavlov's House", but that was about Russians seizing and defending a house from a Wehrmacht siege for 60 days. The other part where they mention treasure reminded me of Kelly's Heroes (every GuP fan should know about Kelly's Heroes), but in that film, the original party seeking treasure were US soldiers blocked by a German tank defending an unrelated objective, and one of the guys successfully convinced them that if they cooperated by blowing up the vault door of a bank with the tank's gun, they'll split the loot and leave on peaceful terms (IIRC).