Recusive <section/>'s and their conclusions

I want to markup my docmuments in the following style:
<article>
   <title/>

   <highlights/>
   <highlights/>

   <section>
     <title/>
   </section>

   <section>
     <title/>
   </section>

   <section>
     <title/>
   </section>

   <para>CONCLUSION</para>

</article>

but due to current DTD restrictions i'm not able to do that.
I DON'T want to use another section for CONCLUSION, cause it haven't got title that is 
mandatory for the section.

What am i doing wrong? Is there any ways to solve this task?

Thanks in advance,
Dimitry.