Can anyone give me advice on choosing relationship designators for this complex instance?

Bodies A, B, and only part of C merged to form Z. Z belongs to a French university that was formed by the merger of three universities. The merging bodies belonged to two of the merging universities. In a sensible move, the merger that formed Z took place on the same date as the merger that formed the new university. What became of the rest of C is unknown, but it may have merged with some other body.

When a split and a merger take place at the same time, does the split or the merger take precedence in choosing relationship designators? Is this situation documented anywhere? Both choices feel awkward to me.

110  A [or B]
510 $w r $i Product of merger: $a Z

110 C
510 $w r $i Product of split: $a Z or 510 $w r $i Product of merger $a Z ?

110 Z
510 $w r $i Component of merger: $a A
510 $w r $i Component of merger: $a B
510 $w r $i Predecessor of split: $a C or 510 $w r $i Component of merger: $a C ?

Diana Slaughter
Law Library
The University of Michigan
Ann Arbor, MI  48109-1210