That's impossible, if you want to listen to modern singers like Rossana you will have to do it on radio-formula programs like 40 principales, etc... that mix Spanish pop with the rest of the comercial pop music from all over the world.
There are to rados with only music in Spanish Cadena dial (more close to latin music, here you could listen Rossana) and Radio Olé (copla and flamenco).
I like some programs of Radio 3 (RNE) very different from commercial pop music, but not usually centred on Spanish pop