Aspects of the relationship:

Serial A splits into two or more separate serials (serials B, C, etc.) each of which continues part of serial A; serial A ceases.

New serials may have entirely different titles or common title/part title.

Numbering may be the same for each with the addition of a letter (e.g., v. 138A, v. 138B, etc.)

Linking entry fields:

CONSER practice:

Serial A: 580 note and one field for each related title tagged 785 16

Serial B (C, etc.): one field tagged 780 01

Non-CONSER:

Serial A: one field for each related title tagged 785 06

Serial B (C, etc.): one field tagged 780 01

See also:

14.2. Chronological relationships (fields 780/785)