.red { background-color : red }
div.stub > p + p { background-color : lime }

<div class="stub">
<p>This paragraph should NOT have a green background</p>
<p class="red">But this one should have a green background</p>
<p class="red">And this one should also have a green background</p>
<address>This address is only here to fill some space between two
         paragraphs</address>
<p>This paragraph should NOT have a green background</p>
</div>