Okay so I finally got my component to work the way I want it, so thanks to both Eric and Michael for steering me in the right direction.

Especially Eric for his own version (which I almost used instead) which helped me learn more about the OSSN platform through practice and application of similar technics.

Hi guys, sorry I've been very busy lately and couldn't find the time to get back here. Would it be better if I upload what I have done to date so you can see what I am attempting to do? I have most things working just cannot figure out how to get the component to actually create the private group after saving the new group. It just stalls. For the record I am not that experienced with coding so I have been working with AI to help fill in the blanks. Hopefully this won't offend anyone.

nice component, slug(my component works)
https://nlsociaal.nl/test/g/secret-private-group
and indeed its secret. now the way to override the 404 page with
" To bad, this group is secret"

Yep, some way to let the invited user know the path of that group would be fine. ;)

My idea for the Private Groups component I created yesterday was to maintain compatibility with the familiar workflow of Ossn core groups as much as possible.

a oke, but with an invitation you need still an url to the group?

I don't think so, Eric.
To my understanding Paul's original intention was to keep a group of type 'PRIVATE' completely invisible:

1. as long as you are not already a member of that group
   or
2. have received an invitation to join

put my alteration online

https://github.com/compie67/ossn-groupinvite-advanched

Think i got it
https://www.opensource-socialnetwork.org/component/view/3305/group-invitation

altered this component and now you can share, and invite users to your closed group

Okay. Back to this topic. Indeed you want to have some invites option to the shared closed group. My example group about am sickness. Now i can share https://justbsocial.eu/g/nah-er-gaat-veel-goed but there is no join(redirection when no account present) new users have to make an account, become friend and group owner can invite. Understand the hussle

Okay, for me got the solution.
made an time line filter and group post module

What was fixed and why

We discovered that private (closed) group posts were leaking into the main timeline for users who were not members of those groups.
Although OSSN correctly blocked access when clicking the post (showing a 404), the timeline override was rendering the post content without checking group membership, which is a privacy issue.

What we changed

1. Added a strict group check in the timeline view

Before rendering any post:

If the post belongs to a group:

Public group → the post is shown to everyone

Private / closed group → the post is shown only to group members

Non-members never see private group posts in the feed anymore

This prevents content from being visible in the timeline if the user is not allowed to access it.

2. Improved the SQL filtering logic

User posts still respect their access level (public / friends)

Public group posts are allowed in the homepage feed

Private group posts are not blindly filtered in SQL, but are safely handled in the view layer with a membership check

This keeps public groups discoverable, while maintaining correct privacy for closed groups.

Result

✅ Public group posts help attract new members (intended behavior)

🔒 Private group posts are visible only to members

❌ No more “visible in feed but 404 on click”

🛡️ Privacy is enforced consistently at multiple layers (defense in depth)