Using subtype property of the esriaddinx for a AddIn button

I am trying to utilize the subtype property of an AddIn toolbar button in C#. In older versions of ArcObjects this could be accomplished using ICommandSubtype and extending the BaseCommand. However, I cannot see how to do it in the current ArcGIS 10.x AddIn model.

I would like to implement this functionality, because I have multiple buttons that will simply write out a single field value to a selected feature. I do not want to have to create multiple classes for each value. Being able to use the subtype capability of a single class would be ideal. I noticed that the "subtype" is available in the intellisense of the toolbar button in the .esriaddinx, so can this be done?

Is there a way to extend the ESRI.ArcGIS.Desktop.AddIns.Button and use the "subtype" property?

I am developing for ArcGIS 10.4.