Unable to create meaningful relationship in Power Pivot

Hello All

I am slowly learning the capabilities of Power Pivot, but there is one scenario that is continually occurring for me, and I can not determine if this because I am not setting the relationships up correctly, or if PowerPivot is unable to display the data the way I am hoping.

I have two tables: Projects & Actions
Both are connected using an "ID" column.

I am trying to make a summary table listing ALL of the projects, and for each project, the actions that are related.
When I try and make the pivot table, I am not able to list ONLY the action IDs for the Project ID that it is related to, and instead list all of the action IDs for every project.

The attached file shows the pivot table I am currently getting, and a manual version of what I am hoping to create.
I believe the issue is linked to the fact that some of the projects do not have actions, but even still I feel I have done something wrong.

Thanks in advance for any assistance.

Is anyone able to give any info on this?
I know this probably has something to do with the one to many relationship I have created, and how Power Pivot handles it.