I would suggest treating the relationship entirely in terms of merge, not split. That is, the only RDs used would be "Product of merger" and "Component of merger". 678 notes can give precise information about the relationships:
In Body A record:
678 "Body A merged with Body B and part of Body C to form Body Z."
In Body B record:
678 "Body B merged with Body A and part of Body C to form Body Z."
In Body C record:
678 "Part of Body C merged with Body A and Body B to form Body Z."
Should the other body ever become known, the note could be changed to something like:
678 "Body C merged in part with Body A and Body B to form Body Z; and in part with Body X to form Body Y."
In Body Z record:
678 "Body Z formed by the merger of Body A, Body B and part of Body C."
Kevin M. Randall
Principal Serials Cataloger
Northwestern University Libraries
[log in to unmask]
Proudly wearing the sensible shoes since 1978!
> -----Original Message-----
> From: Program for Cooperative Cataloging
> <[log in to unmask]> On Behalf Of Diana Slaughter
> Sent: Wednesday, July 31, 2019 11:48 AM
> To: [log in to unmask]
> Subject: [PCCLIST] Relationship designators for merger involving a split of
> one of the merging bodies
> 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