Using Css to display text for certain conditions

Given the Xml below which I cannot change, is it possible to have the conditional results with just css. I can only use css at the moment but css is very limited in terms of conditions from my understanding.

<doc>
<story>
<c1><p><text-web-group class="MajorEvent650x366"><text-web class="MajorEvent650x366">Sample Text C1</text-web></text-web-group></p></c1>
<c2><p><text-web-group class="MajorEvent650x366"><text-web class="MajorEvent650x366">Sample Text C2</text-web></text-web-group></p></c2>
</story>
</doc>

1. Sample Text C1 is displayed if there is text only in C1/p/text-web-group/text-web


2. Only display Sample Text C1 is displayed if there is text in both C1/p/text-web-group/text-web and C2/p/text-web-group/text-web


3. Sample Text C2 is displayed if there is a text only in C2/p/text-web-group/text-web