Depends what you mean. Too make a hole aligned to a boss or another hole use a COAXIAL hole. You can also use linear placement and selct a reference at that postion. Click in the bock that says offset under Secondary references and change it to align. (WILDFIRE).
IN Wildfire, click the pause button, and place a datum through the axis of the first hole - parallel to the second. Resume, drag one handle to that datum for a 'zero' dimension. I really wish that it could be made that we didn't have to do a datum on the fly, and that we could just drag our handles to the axis. I have noticed that you can use a hole axis if the first hole is not planar to the second hole.