i have using the same url for different languages.
<reference name="head">
<action method="addLinkRel">
<rel>alternatve</rel>
<href>https://www.example.com/</href>
<hreflang>x-default</hreflang>
</action>
<action method="addLinkRel">
<rel>alternatve</rel>
<href>https://www.example.com/</href>
<hreflang>de</hreflang>
</action>
<action method="addLinkRel">
<rel>alternatve</rel>
<href>https://www.example.com/top.html</href>
<hreflang>de-de</hreflang>
</action>
<action method="addLinkRel">
<rel>alternatve</rel>
<href>https://www.example.com/</href>
<hreflang>de-at</hreflang>
</action>
<action method="addLinkRel">
<rel>alternative</rel>
<href>https://www.example.com/</href>
<hreflang>de-ch</hreflang>
</action>
</reference>
But while using this code in category->custom design in manage categories. I'm geting only i url in the page. i check it in page source
<link rel="alternative" hreflang="de-ch" href="https://www.example.com/" />