Yes you can merge them into one and use the logicalGrouping for the conditions and set it to Any which would be the equivalent of an “OR”. For example:
<rule name="Force WWW and SSL" enabled="true" stopProcessing="true">
<match url="(.*)" />
<conditions logicalGrouping="MatchAny">
<add input="{HTTP_HOST}" pattern="^[^www]" />
<add input="{HTTPS}" pattern="off" />
</conditions>
<action type="Redirect" url="https://www.zzz.com/{R:1}" appendQueryString="true" redirectType="Permanent" />
</rule>