If you are using LabVIEW, you can use the "Generate Pulse Train (NI-TIO).vi" example. With this example you would toggle the source specification to be default PFI line and specify the raw counts. For example, if you wanted to divide your input frequency by 8, you would set the delay and pulse to 4. You then plug your input freq into the default source PFI line for the counter you're using (PFI39 for counter 0, etc.). The divided signal will be available on the output of your selected counter.
Hope this helps.
gusg