We strictly don't allow the posting of duplicate articles on either the same or different portal websites.
A LOT of time was spend to optimize the system for SEO (Search Engine Ranking) and the search engines "hate" duplicate content.
You can post articles on your own website and a portal website, but then add the URL of the article on your website, as the "Source" on the protal website as search engines will then recognise YOUR website as the source of the original article.