We work with a lot of tools that are "certified" either by ABS, DnV, etc.  In that we have submitted drawing packages with all the approved weldments for that particular tool included and these drawings are stamped by the approving authority.  However, even though we manufacture the same tool over and over there are nearly always slight differences.  These changes are not primary structure but small items such as light brackets, cable tray, etc.  What I want to do is to use the same weldment each time (same part and part number) but then use that part as the "start part", for lack of a better term, for another weldment.  In other words, if I had piece of welded steel of some sort that was approved I would want that same weldment to be used the next time.  However, like I stated, there would be slight differences.  I need the approved P/N and the weldment to appear in the cut list as an item in the next level weldment.  I do not want the entire cut list to be shown, just the top level part number of the base weldment.  Otherwise, we have to make a complete new drawing, with a new part number and a new submittal package each time.  This is costly both in the money we pay those guys and in the amount of time that we take making new drawings each time.

I need, in an ideal world, for the base weldment to be "linked" into another weldment so that if we do make changes to the base weldment it is updated in the next level.  Am I making any sense?  I want weldments, in this regard, to behave just as an assembly does wherein a part or assembly that is in the next level shows up as a single line item in the BOM and is updated whenever changes are made.   I am skeptical, given the limits that there are with cut lists and the like, but does anyone know if this possible in SolidWorks?  If not, any suggestions?

Thanks in advance for any help!