Hi Arun,
In the past (must have been Clarity version 7.5.3), I have used Rendezvous to execute multiple steps in parallel in a workflow. However, given the ability to create multiple actions in a single step (which was added in subsequent versions), the need for using Rendezvous type split has diminished.
Now, to your question - if the three approvals are different (in terms of the action item description, nature of approval), a rendezvous type split may be appropriate. However, if it is the same action item that you are seeking approval on, I would suggest using a single step with multiple assignees for that purpose. In the post condition, you can always check the approvals before you move to the next step.
Thanks,
Regards,
Debroop