Long term valuation

[Brendan Hayne]

I learn a lot from reading the posts on this forum and I would appreciate the expertise of the community.  My business partner and I are thinking about how to pass along the properties in our portfolio to our children.  Our kids don't really know each other and probably wont want to be forced into business together.  So how do we equitably divide the portfolio?  If it were just current market value it would be easy but some properties have higher rents or lower costs to maintain that have to be considered.  

So is there a common formula that people use to valuate a property considering all these factors? Market value, value of rents annually, costs to own, etc...?