Photoshop :: Pen Paths (brush Stoke) Filled With Color Only On Selection

This is what I'm trying to make...

The black lines would be the pen paths (curved shapes) with a brush stroke, but then I would like to select an area of all those pen paths lines (like you for example do when using marquee tool) (in the example green color) and fill the path lines with for example green only on that selected area and the rest stays black in this case and only the lines would be filled, so not the white space between. I kind of did it in Illustrator using scissor tool, but cutting all the paths takes a lot of time and precision so I thought there might be a better, easier, more precise way to do this in photoshop. how to accomplish something like that?