What are some good ways to change a property on multiple files at once?

I am trying to figure out a good way to apply an (already assigned) ECO number to the drawing and references.  Our process is to create the ECO file using a PDM template and then paste it as a reference to the drawing it affects.  The drawing, ECO, and all other automatic references (parts, assemblies) then get transitioned at the same time to the next state in the workflow for checking, etc.  The ECO number is needed on the drawing because it shows up in the revision block, and on the rest of the files just for consistency.  The value is already on the data card for the ECO itself when it is created.  Presently we have to manually edit each file data card and add the new number.

A nice way to do this, in my view, would be to ask the user at the point of transitioning what the new ECO number should be, and then assign that value to the appropriate variable.  Is there a way to get user input for use in setting variables during transitions?

Another way would be a tool that lets you select a group of files and edit the properties all at once (actually this would be useful for a lot of things), but I can't seem to find a way to do that either.

Any advice?

Thanks

Megan