PHP based GUI time management app for school teachers.

Hi. We offer one on one classes on internet. For this purpose we have 3 teachers. Each teacher is going to teach from 9:00PM to 6:00AM every day. One student can learn 10, 20, 30, 45 or 60 minutes class , 2, 3 or 5 days a week. Currently i am using Microsoft Excel to note the timing of each student with each teacher. but the problem is , i can't make this Excel file live on website. because 2 administrator are going to manage this file every day from two different locations and 2 different computers. So we need a PHP based GUI for the time management for our teachers. I have attached screen shot of our teachers management system in Excel to this project. i need the same and better one. The file is actually having 30 minutes schedule. but in PHP app we need it for each minute from 9pm to 6am (office time) .