Suggestion for a future version: Allow the vertical bar | as an include-list separator, behaving just the same as the semicolon. Then in some more-distant-future version, the semicolon could be deprecated.... Filespecs containing a vbar would need to be quoted, of course, just like spaces, ampersands, et cetera.
(The choice of semicolon for this function goes back to 4DOS. IIRC, semicolon was not a legal filename character in DOS, so it made sense at the time.)