The only times a full 32 player party was realized was during the latter JDC season's opening events. As far as I remember, not even the latter Bashes could reach that amount of players and the earlier Bashes didn't have Plus to utilize the extra connections.

So if you don't want to put in the effort of trying to organize an event through JJ.net as MS stated above (which is a good suggestion), you could also wait for the community to organize a new JDC season and try to claim a place in the opening event. Just create an account on JDC at any time and keep visiting the J2O newspage and it'll eventually happen.