I want to set one custom field that will apply to several properties. This isn't currently an option in your system, This should not be hard to do as you already have the code to pick out specific properties.
Here are use cases, for example:
Trash Collection
Neighborhood amenities
Disclaimers
General Guest Instructions
Specific Owner Rules applied to an owner's properties
As it is you need to add a field into each property which completely defeats the purpose.
From your tech
"As the type of field code needed for what you're hoping to accomplish is a property type field code, our system currently has no way to automatically batch update the custom fields for any properties of your choosing to match the custom field of the 1st property you configure that custom field on.
Thusly, manually configuring the custom field per property is necessary"
custom fields already apply per property. You need to populate it with data specific to each property.