Starting 1.19 in each property you can attach other properties as subunits. The subunits are also properties so they will show in properties search results.
First publish your properties.
Published means that have status published
View from admin
View from front end user dashboard – my properties
Next edit the property post for the building – and select the subunits from the properties list
This is the admin view for how to select subunits.
Use CTRL to select multiple units. In admin only the first 50 published properties show. If you wish to select properties that are not in the list, add the IDs of those properties in the ID field (help to see ids -http://help.wpresidence.net/2015/10/29/how-to-see-ids-for-shortcodes-and-widgets/)
This is the front end view to select subunits. Edit a property and go to Subunits sections. Select which properties to show as subunits and save.
In front end the property set as building with subunits will show all subunits like this.
The title of the subunit will redirect user to the subunit property page. On that page other subunits will show like this
The titles: Other Units and Available Units can be changed with your own labels from theme options – custom labels