How to determine the limit of group delay distortion for BPSK in IF filters

Hi all. I have a question about how to determine the limit of group delay distortion for binary psk when IF filter is used. I dont know how I can decide the value. Please help..

Thanks

Because group delay affects BER it depends by the BER target, and also depends by the type of the filter used, by filter order, and by filter bandwidth.
The best answer can be given by a system simulation, which includes above inputs.