Multiple Hiers!? How to force a sale with majority

[Ashton Fry]

Good afternoon, I am in communication with a seller who is a part owner in a MFH. She is 1/7 owners and her other three sisters want to sell too. This would give me 4/7 owners that want to sell the property. I have heard that a lawyer can force the sale of a property with multiple hiers want to sell. 

How does this work? Anything I need to be mindful of? Any other idea for acquiring property?

Thanks!

Ashton