Change Times

Hi All

Firstly I should thank all contributors for allowing this piece of software to be free!

I know i posted only a few days ago however i have come up with a new idea that may be easier

I am a school teacher and I have been given the task to create a room booking system. As schools don’t go by times as such it would be a great idea if it could go on periods ie 1, 2, 3 ,4 . The version I am using is 1.2.11

In schedule bookings Instead of start time and end time as 1.30am, 2.00am, 2.30 am etc is there any way to change the time format just to show 1 instead of 1.00am, and 2 insted of 2.00am as this would indicate periods etc, using this method would only need ammendments to the time format. can anyone help
Thanks All
Regards
Scotland0