An organization made the reservation, not a private party. No one was discriminated against, because no one made the reservation.

Two different organizations were involved here . A "restaurant" made a decision not to host an "organization". There were no people involved - at all.

I am a business owner and I hire people - not organizations. My employees chose to work for my organization - not someone else's organization.

My restaurant is a restaurant - not a public meeting space.

If this group made a reservation at my restaurant, my restaurant would not accept the reservation. I would not ask employees to set-up, serve, then clean-up, and tear-down tables, chairs and a sound system in a private room so another organization could hold a private meeting in my restaurant.

However, if members of this group made individual reservations, my restaurant would serve them. Like everyone else, they would be seated where ever we had a table and servers available to wait on them. Like any other customer, if they disturbed other customers, they would be asked to leave.