You don't.
AutoCAD can only hatch in a single color, or a gradient that changes from one color to another across the entire hatch area.
If you're creating a block to represent a barricade, use two hatches.
If you're trying to hatch a corridor shape using Code Set Styles, you're out of luck for an automated solution, unless you were to put two shapes atop one another and apply different hatches to each. I've never tried that but it might work.
Tim
You can also use a background colour which may work for you
neilyj (No connection with Autodesk other than using the products in the real world)
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Boy do I feel stupid. There's the OP's answer, just turn on the background color.