Dear Vishal,
Let me try to explain the scenario with the below example
As you can from the above screenshot Almika SA is the company belonging to India. It has 4 business residence(Red Block) under it with all residing in India, hence all of them take the same currency as Country of registration that is INR.
However if the greenblock is what you intended to create. If you select this org unit as company then you can select any country of registration example : Australia will have AUD.
But legally speaking am not sure if you can have this registered a company under company.
However if you select this org-unit as business residence, it will take the currency as parent company which in this case would be INR.
Technically speaking you can create a comp under a comp with different currency but this cannot happen at business residence level.
Regards
Leo