The attached pdf file provides you a visual plus an exercise you can use with two groups discussing a pending merger, collaboration, or other joint work.

1 to 10: What Merger Looks Like
(2-page pdf file)

For more on mergers, read:

Five Steps to Take Before You Move Forward with a Nonprofit Merger 

Nonprofit Merger Checklist: The Ten Steps

Also, find this Meeting Planning Document: A useful form to help you to decide and record the critical details at your meetings and increase accountability.