How a constructed house divide among legal heirs

Admittedly, the property is not divisible. Hence, approach the Court through a partition suit.

Yes, if among legal heirs amicable settlement is not possible, it is better to either go for settlement through court or sell the property and share the proceeds equally.

Your piece really turned the light on for me to the extent this particular topic goes. https://www.google.com

If there's no consensus arrived among the shareholders for an amicable partition then the next option before you is to approach court of law for remedy and solution to overcome the crisis. 

You three alone cannot divide the property as per your decision without involving the agitating shareholder.