Private Event Room for a group of 20

Hi! Live out of town but we are looking to plan a private event for my grandma's 90th birthday. With her club under renovation, nice private dining spaces (a private room) for around 20 people. Target budget would be around $100 a person, but no set number.

Any restaurant suggestions that might meet these criteria? So far planning on exploring City Fish Market and Sixty Vines.

Thanks in advance!