Dear Vandana,
You may check with IIJT. They had plans to conduct training across India simultaneously. Their all the centres are connected through V-Sat. You may visit their office located in your city. Couple of years ago, I had been to their Bangalore centre. You may use their facility if they are ready to rent out. When you use their facility couple of times, you may come to know the technical glitches. Their website is as below:
Indian Insitute of Job Training
Once I conducted training for very prominent IT company in Bangalore. The programme was broadcasted at two other offices in Bangalore, Hyderabad and Chennai. However, at other place, participants could not see me on the screen but they could see the presentation. My voice and outstation participants' voice was audible to each other. Whenever any outstation participant raised a query, it landed in coordinator's laptop. The programme had started late by half an hour because of loss of link. But once started, there was no breakdown in between. All this happened couple of years ago and possibly advanced technology might have come in.
By the way, have you tried Go to Meeting? If you use their services, your investment may come down. Participants can attend the workshop. They should have their laptop and good internet connectivity.
All the best!
Dinesh Divekar