No force is needed.
All I hope for is if both Governments just put in place the mechanisms for such a transfer. I am 100% sure there will be many takers. Nations should not become prisons. That's all.
Like I have people who are settled here but long to move to BD. Except they can't because their property is all here. A property transfer mechanism can ease many issues so that people moving are prosperous migrants and not begging refugees. Dignity of life can be ensured. Non Muslims from BD and mostly Pakistan keep pouring every year already. Only they are forced to stay in the poorest colonies because their wealth(back home) is worth nothing here.
There is nothing stopping a BD Hindu from selling their property and moving to India if they wish with their money.
You forget the emotional attachment that people have to their country of birth.
Very few Hindus from BD are moving to India these days as the economy is relatively good and there is little discrimination against them - not saying there is none as people will be people at the end of the day.