I would probably opt to use relations in both parts where you can "wholesale" replace the values with a cut and paste. This would avoid dependencies between the parts. You can tie the relations directly to the section feature rather than the top level if you would rather bury the relations a little deeper than the surface. I like this simply because it is easy to manage and the part file remains wholy independent;
Another method is to make the component flexible and drive both parts at an assembly level making them equivalent at that level.
I'm quite sure you can use a few other tricks to drive this from external data but you have to look at how these two similar parts will be used at next level assemblies. Are they indeed fully independent where both part will rarely be used together? In that case I would definitely want to avoid dependencies.
A family table might even be more desirable. You have so many options to drive "common" components that you have to consider context and sustainability.