Don't bore/notch in middle third of a joist... span or member?
Answering my own question after a more thorough reading of the spec.


  R502.8.1 Sawn lumber. Notches in solid lumber joists, rafters and beams shall not exceed one-sixth of the depth of the
  member, shall not be longer than one-third of the depth of the member and shall not be located in the middle one-third of
  the span.


And it includes this very helpful graphic:



So the answer is:


A bearer does make a continuous joist into two spans.
I can notch between 0'-4', 8'-16', and 20'-24'.