Saturation over brightness in Photoshop

I would first verify why the images are over saturated - is this a colour management issue.

There is no such function. You can do it with masks, but it is a crutch and not the best. It is the same as making a mask by lightness and working with exposure with the offset tool (if such a tool existed).

Blend if-settings might also be useful, though they offer less editability than an outright mask. 

In Photoshop, as Trevor said you can apply a Saturation or Vibrance adjustment layer through a luminosity mask which should give you more control than some of the other options below. Or, some apply a Curves adjustment layer with the Luminosity blending mode applied so that the contrast adjustment doesn’t affect the color.

Another approach is to edit the image in Adobe Camera Raw, or if it’s a Photoshop layer choose Filter > Camera Raw Filter, and when you adjust Curves, also adjust the Refine option, which refines how much that saturation is changed by the point curve adjustment.

Or, again in Camera Raw, the Color Grading options let you adjust saturation for each of three tonal ranges (highlights, midtones, and shadows), but in Color Grading you can only increase saturation, not decrease existing saturation.

Unfortunately, the curves in Adobe photo editing applications have no direct equivalent to the advanced curves such as Luma vs Saturation that are available in Adobe Premiere Pro and other video editors.

https://motionarray.com/learn/premiere-pro/hue-saturation-curves-premiere-pro/

I am not entirely sure what you mean, but I think Luminosity Masks might do what you want.  This one from Sven Stork is very good, and is also free.

https://exchange.adobe.com/apps/cc/12307/interactive-luminosity-mask