I recently had a quite deep look into Jive's entitlement checking and as far as I recall, the system first checks entitlements related to the container, so it won't even get to the content itself. This might be an opportunity for a custom content type that has a different way of checking entitlements, but that would be a lot of effort to implement (as every other content type).
+1 on what Tobias said.
I would add this. If you have a space (and not a group) then this is the opportunity to rethink that space. Perhaps creating a parent space that has the rights you want for additional users to view. Then a subspace (the members only) area where the rest of the content lives. This allows you to let the members only users create content in the parent area when they want to expose it to others but still have the original members only area for more restricted content.
So I don't think you have a development issue here. You have a community design issue.