Time between two dates [including working hours only]

[gp2012]

Hi, I have an excel with start date and end date, and I want to only include working hours in the calculation of the difference.
Currently I use NETWORKDAYS to exclude weekends and holidays, but How can I also exclude any hours that are not between 8.30AM and 5PM?

my time is DD/MM/YYYY HH:MM:SS

 

[Derek Brown]

Perhaps the following will help:
Calculating working hours between two dates