Guided selling with zoho crm?

i have couple of interns working in, and i want them to take an organized approach while selling.

This is what i want-:

1. I will have 5-6 sales stages

2. Each stage will have pre-defined tasks

3. Whenever a lead gets converted into an opportunity and enter first sales stage, system should automatically assign all pre-defined tasks of that stage to lead owner

4. Lead owner should not be able to move the opportunity to next stage unless he finishes all the required tasks

possible with zoho crm? how?

thanks