There is no relationship between authoring a single Outline for multiple offerings and the merging of cohorts within a subject site. Once the Outline is ready to be published, the tool will split the single Outline into a distinct Outline for each offering which will be published to the relevant student cohort within the subject site for their enrolled offering. See Figure A and Figure B below.
Important Academic Senate regulations relating to Subject Outlines (Academic Manual L6.3 - section 1.2 Issuing Subject Outlines) states:
A subject outline shall be prepared each session for each subject being taught by the University in a particular mode in that session. |

Figure A. An Outline created for a single offering will publish to the student cohort within their subject site.

Figure B. An Outline created for multiple offerings will publish a distinct Outline
to each student cohort within the subject site for their enrolled offering.