Managing visibly different sizes of multiple fonts being used

I'm using 2 different fonts in a responsive website. The problem is that the 2 fonts look very different at the same size. And so, I need to somehow alter the typography rules based on the font-family. I can always use a class wherever I'm using the secondary font and manage the sizing, but then I'll have to duplicate the responsive typography rules.

Is there any easier way to do this? Like some font-* attribute that scales the rendered font-height, or a font-family based selector?