Sentence:  For the occasion on which everyone already knows everyone else and the host wishes them to meet one or a few honored newcomers , then the `` open house '' <WSD>system</WSD> is advantageous because the honored guests are fixed connective points and the drifting guests make and break connections at the door . 
Meaning of the word marked with <WSD> tags:  instrumentality that combines interrelated interacting artifacts designed to work as a coherent entity