Multiple Objects as a Mask

If you try to use more than one object as a clipping mask, only the last object you created will act as a mask the others will be ignored. To use those multiple objects as a mask, you'll first have to select all the objects and from the Object menu, choose Compound Path>Make, or press Command-8 (PC: Control-8). Then position the compounded objects on top of the object you're masking, and use the Object>Clipping Mask>Make command, or press Command-7 (PC: Control-7).