Hey @aparisi
You have entered the realm of HubSpot middleware applications! There are some techniques to make sure your data synchronizes with HubSpot. One of them is to download quite literally everything onto your servers so that you can have your system manipulate the data to return to HubSpot. This is the technique I use to get around the inconsistent error messages thrown by HubSpot’s API.
As for your question, I do not think there is a way to create a custom ID that follows the same error reporting as the other properties without the devs introducing breaking changes.
Hope that helps!