One Dependency for the start, another for the end?

Hi... I'm trying to set up a project that has a task (weekly update reports) that begins with one dependency (e.g., start of project), and ends with another dependency (e.g., on-site work). There are still some administrative tasks that continue after the on-site work is done, but I won't have to continue the update reports for them.

I've tried to set up a SS dependency on the top Predecessor line, and a FF dependency on another Predecessor line, thinking that it would tie my duration to both the Start of the project and the Finish of the on-site work. But that doesn't seem to do the trick.

I've also tried to use a cell-to-cell reference for End Date in the End Date cell of weekly update reports (=[End Date]9) but that doesn't even calculate. Probably trying to use Excel reasoning, lol...

Any thoughts?

Thank you very much for any help!!