Hi Bronwyn
This is how I would approach this:
1) Create an external_choice list that contains the address, suburb (if using it) and asset ID and use this as the basis of an address select_one. On publishing - this will create a .csv in your media folder that you then apply pulldata() to, in order to return the asset ID based on the address selected.
2) Use cascading selects to apply a choice filter to limit the list of addresses - you could filter by suburb for example.
3) Use the autocomplete appearance on the address select_one question - so that you can start typing to further filter your results - before making a selection.
4) Use pulldata() to take the selected address and use it to look up the assetID for the property.
Attached is a simple example
Please let me know if you have any questions.
Thanks
John