I think it would be useful to separate them for models that offer more than one two-door bodystyle, like the Mustang, Celica and Nissan SX models. For cars like the Probe, 3rd-4th-gen Camaro/Firebird or Scirocco, it's not as much of a concern.

The only one where it would get tricky would be the Geo Storm, which had two different 3-door models. I guess also the AMC Spirit/Eagle SX4 also had an issue with the slopeback and kammback versions.