@Jeff @Jonathan_Doe, we’ve decided to accept this feature request to introduce advanced options for the single select field. This will allow one single select field to depend on another, with the ability to choose dependencies per option.
Please note that while we will implement this feature, it is currently a low priority. As with all features, we may increase its priority if we receive more user requests for it. 
@Jonathan_Doe regarding this example you’ve shared:
In case you didn’t know, Baserow has conditional logic functionality in the form view.