Allow posts in Umbrella project to go to members of associated collection projects

The reason for creating umbrella projects is to link individual projects. In doing so it would be great to be able to connect with all the people participating in these projects as well. Creating news posts in the umbrella would often be of interest to participants in the individual collection projects under the umbrella, but the only way to do that is to copy and paste the post into each project.
I can foresee a concern that umbrella admins are able to add any project and the creators of the collection project may not want those messages to get pushed onto their members, so this feature could be made to apply only to collection projects created by the same admin(s) as the umbrella.
Thinking this through, it would also be good to be able to decide whether the post gets sent to collection projects (and which ones), or just the umbrella - so perhaps have a check box beside each project that meets the criteria of having the same admin.
Here is a good example: Parks Canada has an umbrella under which all the National Parks projects fall (47 of them). I could see how they would want a single national post to be able to go to all 47 projects at once.