The key here is to parse openApi JSON file for the desired content. You could afterwards convert it to a format used by your archbee documentation platform, here Markdown, but in separate files so you can do manually add content.

For that you could use a script in your favourite language (eg. Python) with parsing modules. Of course if the json is only available thorough the internal network, the script will only be able to fetch the data while on it.

Another factor is how you want to automate the process, you may be able to trigger the script automatically for a certain period in time for example every day or each time the JSON file gets modified.