Restrict contacts from knowing I am on WhatsApp Am I right in understanding that when one installs whatsapp everyone in the contacts on my phone knows I am on whatsapp (at least the ones who have whatsapp)

I do not want the above to happen. So if I put in another SIM card, then can I avoid the contacts on my primary SIM knowing I am on whatsapp and restrict to only the contacts on the new/secondary SIM. Or will WhatApp anyway broadcast to all contacts on all SIMs? 

My basic aim is to expose the fact that I have whatsapp to a limited set of people - hence the second SIM. 

Kindly let me know

Ananth
Simple answer to your question is - everyone who has your new number will see that you are on WhatsApp. WhatsApp is tied to mobile number only and it will not "broadcast to any other sim". If you don't give this number to another person then they will not be able to  see or contact you.

Also a hint. If you have dual SIM phone you can use normal WhatsApp and business WhatsApp (it's free) on the same phone simultaneously (using 2 different numbers).