A homeowners association (HOA) or property owners association (POA) is an organization created to maintain the appearance and common property of a group of houses, typically a subdivision.
There is no agreed upon tagging scheme for HOAs, particularly in regards to subdivisions within an HOA.
One possible method is to tag the boundary of the HOA as boundary=administrative, with admin_level=10, or whatever is appropriate for the local area. Some HOAs are further divided into neighborhoods, and neighborhoods divided into clusters. Increase the admin_level for each successive level.