We're doing our welcome dinner at Ohana. I made 2 separate reservations for 5 minutes apart (2 separate
MDE accounts) for 30 people each. 30 is the max the online system will allow you to put on a single reservation (possibly also the max they'll allow you to book through the standard WDW-DINE line as well). Then I called up Ohana and spoke to someone and let them know that we have 2 reservations and they told me it's not a problem to put us all together.