Hi OP,
I am organsing a group of 100+ students on CX; BKK-HKG-NRT in November and I'd like to share what I have done here. I had contacted CX office in Bangkok stated the destination and number of my group. According to the CX agent, she had to put those details and bidding price into their systems in order to get the quotation which is around 100 USD chepaer than V fare that I have bought for myself.

So, I would recommend you to contact your local CX office and inform them your requirement. I don't know if they have minimum amount of passengers required but it couldn't hurt to try. Hope this helps .

S