Add r/o/y/g/b/i/v to foreground color?

hello...

Is there a way to have image/adjustments/color balance affect the current (foreground) color instead of the existing pixels on the layer?

For example-

if my current foreground color is red (in the tools panel), when I paint in my document with a brush, it paints red (obviously).

Now - I want to add a bit of yellow to the current brush/foreground color (which is currently red).

Is there a slider which would allow me to add some more yellow to the foreground color (much like the color balance sliders?)

seems like a simple request, but I haven't been able to find something like this so far..

thanks!!