First, before opening anything, set your first assembly AND THE DRAWING for it, to "read-only". This is just to make sure that you don't accidentally overwrite them.
Click File>Open and highlight the first drawing. Click references. Double click the assembly in the references window list. This pulls up another "Open" dialog box. Select the second assembly and click OK. Click OK again to open it.
You will get a warning that the drawing is "read-only". Click OK. The drawing should now contain the second assembly with all of the views identical to the first drawing. All dimensions and reference geometry (centerlines, center points, etc.) will be broken.
Now, you have 2 choices here. You can simply save this drawing as a new filename and clean-up all of the broken references. Or, if there is already a drawing created for the second assembly, you could copy and paste the iso view of the redirected drawing into the existing drawing.
I use these methods all the time on similar parts such as pins. It works well for me. It is very important to set the original drawing to read-only. It is just too easy to accidentally click save and screw-up all of your references.
Hope this helps.