I'll gather the whole people. There is no private room as you said, but I know that Yang Fei and Bofeite have good conditions, but I have never been there. I can give you their contact numbers for your consultation.
Yangfei Badminton Club -(043 1)84606668
Erdao District, Changchun City
Baofeite Badminton Club -(043 1)82726633
No. Xisantiao 13, Kuancheng District, Changchun City