The electric slot cutter does a fairly good job of removing just enough material that this is not a problem.

If you can do this right up against the existing hing, if anything the area is a bit stronger due to the bond to the hinge and the other side that is already hardened.

I will NOT do this with hand picks however. I tried once and I could never get good results attempting to remove the adjacent area.

The Electric slot cutter solves that.

Of course to REALLY play it safe you could pin the hinges too.