managing multiple properties with one app

[Todd Groom]

I wasn't sure how to even search for this question. Currently, we are using Stessa and Cozy for our units. We have at this time 2 properties with 5 units with the first owner. We are purchasing a third property that has an additional 2 units that will be shared between two owners. Then the second owner also has a few properties of their own. This is a multiple part question I guess. 

First, How do you track basic business costs between all of the properties? If it's a property-specific purchase its easy, you just add that cost under that property. But if it is a shared cost say you purchase a bulk item like a case of caulking or a tool that will be used on both or all properties, how are you all adding that into your cost? Are you just picking a property to put it under? Or are you using software that divides it along with all the properties? It bothers me because if I add it to the property I'm working on today it throws off that properties numbers. Or am I just overthinking this?

Second, managing a single multi-family property with two owners. This is another tough one for me at least. So I own 2 properties and son half of one and the other owner owns 2 properties and soon the other half of one. He has his in Stessa for tracking as do I. How do we manage that 3rd split ownership property? 

Any insight from people who do this now or management companies would be nice. I don't feel we are at the stage of needing any sort of a management company and this is my sole job right now so I've got the time to learn. Thanks for the help.