Can you help with following questions for better clarity on your issue:
1. What industry is your organization?
2. Why do you need such bonds and that too for prolonged 3 years' tenure?
3. What kind of amount should an employee pay (in your or your firm's view) if (s)he breaks the bond.
4. Who would be signing this bond - all employees or only a specific department?
Also note that:
Any kind of bonded labour or service is illegal in India. Service bonds are not acceptable and not viable in legal processing.
Okay there are firms who ask candidates to sign a service agreement but the bond breakage charge would be limited to the cost of training provided. (So if no training is provided, employee is not liable to pay even a penny)
It is inevitable to know why do you want to put such clause in employment to answer to your query.
Kindly revert back with the answers to above questions.
Please red through the following links which will help you understand the service bond better:
16th January 2013 From India, Mumbai