Beware for any tension between participants of different communities/nationalities (i.e. of any discrimination), and if you notice any maybe change the teams of one of these participants. If someone isn’t being involved much try changing the position they are playing in.
Also make sure you give the participants plenty of time to communicate between parts 2 and 3, so they can learn new phrases of another language (this period can also be used as a water break for example). Do also note that realistically this activity can be done with many team sports (like football, basketball) if volleyball isn’t popular in your country.