How to use relative_url_root on internal page link in Alchemy CMS

Question

I have my own root url as: http://localhost:9292/myownsite/. In a EssenceRichtext textbox, I would like to link a internal page to some string, like page-url in its AlchemyPage.urlname. But the link displays localhost:9292/page-url instead of localhost:9292/myownsite/page-url.

How to add this relative url root on?

Thanks.