The most conveniant way:
Get yourself the quite basic Exa or Exa 1a. It yields the ability to substitute the take-up spool for a type 135 cassette.
Though you need a reloadable one as you have to twist its spool.
With the advanced Exacta this might work too, even with standard cassettes, but you should check whether the mouth of the cassettes does not interfere with the sprocket wheel.