It could be done and it might actually be useful. You could fine tune one of OpenAI's models on the material owned by the company and use RAG to create bespoke

It could be done and it might actually be useful. You could fine tune one of OpenAI's models on the material owned by the company and use RAG to create bespoke summaries or quotations to fulfill the user's request but if you're going to do that it might be better for each of those companies to provide an API that ChatGPT (or any other LLM) can call directly and provide a few capabilities like getting all pages published within some date range or by a specific author or in such and such category and also provides a search endpoint that can handle both full text and similarity search. Then as long as ChatGPT correctly makes the function call when asked for a link it should be able to return the exact URL or a handful of results in cases where it is unclear which article the user is asking for e.g. if they misremembered the title and author and provided a vague recollection of the content.