<p>The acceptable way to do the nearest thing to what you want to do, according to the current consensus, is to</p>

<ul>
<li><p>Link the question across the different sites</p></li>
<li><p>Edit each version to suit the different topic area of each site,
rather than posting word-for-word copies</p></li>
</ul>

<p>The first seems quite uncontestable: if someone who fancies answering is told about the other versions they can decide for themself whether they'd be wasting their time or not; &amp; if it's useful to compare responses from different points of view, you should give others the chance to do so.</p>

<p>The second has been contested, but not successfully&mdash;&amp; rules are rules. I can't think of an example where there'd be a statistical answer &amp; a mathematical answer &amp; a computer-science answer to exactly the same question; reaching different audiences isn't held to be sufficient justification in itself  (&amp; as @NickCox has pointed out, they're not completely different audiences).</p>
