Our own rules never clearly specified if moving more than one ball was a foul, so we would currently be deferring to the standard rules. Now it sounds like the standard rules aren't so clear either, lol.
When we re-tighten our own rules we should clear that up. In the meantime, the question should be added to the short list that players who like to ask fresh opponents such questions, along with:
- 3 fouls in effect?
- whole ball or base of ball?
- object ball off the table a foul or not?
- cue ball fouls only -- except move two its a foul (or even potentially interfere with the shot even if you only moved one)