The property left behind by your deceased property upon his intestate death shall automatically devolve on all his legal heirs equally.
However since most of the heirs are foreign citizens and it will not be possible to get a proper legal heirship certificate of your deceased father, it would be better to draw a family tree certificate giving details of all heirs of your father and get it notarised n the local by the person who is residing in India.
After this, all other legal heirs who are not interested in acquiring or inheriting their legitimate shares out of their father's properties, may either come down to India, and execute a registered release deed relinquishing their rights in the properties in favor of other heir(s) who they nominate to to acquire the said properties.
This would enable them to acquire and enjoy the properties without any legal hassle including transfer of all records on that particular individual.
The time taken for this purpose would not extend more than a day of all other formalities are kept ready.
The cost involved would be known locally.