I have a few comments on this thread.

@Sue. We have created an app to integrate Zendesk and Madcap Flare. Please see https://sales.contextengage.com/hc/en-us/articles/212287945. App is in beta but will be released soon. I honestly think the combination gives the best of both worlds - authoring and the delivery to the full support ecosystem
I have been a tech writer for 20 years before becoming a Zendesk partner. The majority of the cases where customers want to use the same article in multiple areas can normally be avoided. It's not good practice. Sometimes a better HC structure and some creative thinking can avoid this use. Even if Zendesk were to allow duplicating articles, I would be recommending against it.

Don't forget it also makes Search less useful for a customer when the same content appears multiple times. I'm happy to help people think thru their structure to try to avoid it.

Even when you have restricted content, I still think there is nearly always a better way than duplicated content.
@Maxime. If you need to copy the same article 5 times, I really think there must be a better structure.
@Jimmy. If I understood your use case properly, there is a solution to your Search request. I'd need to speak to our developers but between regular Search, Labels and coding, it's possible you can get exactly what you want.

If anyone wants to reach out to me, please engage chat on www.contextengage.com.