How tenancy in common works in the real world
When a group of people (or companies) decide to take on a project together, they each go to closing for their share of the property. If Owner A buys 60%, Owner B buys 30%, and Owner C buys 10% of the property, they each get their own deeds, just like they would if they were buying a row of separate houses. This sets them each up for being able to sell their shares later. Any additional agreements will generally be made before taking title to the property and included in closing documents.
Once they each hold title, if Owner B wants to sell their property to Owner D, and no one objects, then Owner D will step into the role Owner B left open. Depending on the rules of the agreement, Owner B can even trade their ownership for a property Owner D owns, giving Owner B a property they don’t have to share with anyone.
If the three owners, A, C, and D, all agree that the property needs a large repair that requires it to be mortgaged, they can also apply for a loan against the property together as co-owners, even though their ownership is legally separate. This gives them more financial flexibility. And if the three owners decide they like working together and all goes well, they can even take their shares of their property and use them to help buy even more properties, which can then be held any way they choose.