You might be able to do that be making a secret collection that is not listed anywhere.

Do you mean by that to create a public collection but don't list this collection on Homepage or other collections? Or is there a special function in creating a collection that guarantees, that posts won't be crawled by search-engine-bots, or other bots etc.?
I tried to publish that blog post which is set for community with a new collection. But the community Flag is passed through.
Could you please tell me how to approach? Thanks

Hi saunders,

You can build a public blog (we name it BLOG B), then at the blog setting: "Settings-> Advanced->Aggregation->Collections to aggregate", enter the blog (we name it BLOG A) id of which you want to public some posts to the others. Then you set the type of one post of BLOG A to public , the others who is not the member of BLOG A would only see the post in BLOG B, but have no permission to do other things except of joining to BLOG A as a member.

Is this what you want?

Regards.

In case I understand the way to feature a quasi "secret url" by the suggested workaround - for me this workaround is not really practicable. The post (set to community) is placed in a blog I have started years ago and 99% of the postings there are public. To unpublish the blog, setting that post to public and aggregate it in another, public blog does not really work.

It would be much easier to think about the feature of secret Url in b2e. This way private or community post could be shared with selected special addressees without forcing them to join the community.

Would a feature that displays "Viewing this post requires a password. If you have the password, type it in below:" work for you?

Yes that would work. But a "Secret Url" with an additional option to set a date of expiry would be more comfortable.
I am no coder, so I am not able to contribute and offer a solution, sry.