P: DNG Converter: Option to turn off conversion of JPEGs

See also my question in this community. I do usually have my cameras set to always save a raw and a jpeg file, with the same basename. Recent versions of DNG Converter convert both into DNG files. I don’t need dngs of JPEGs and this means I need to take extra steps to avoid that. 

There should be an option to disable that and I think that not having DNGs of JPEGs should be the default setting.