How to model government organization hierarchies so that the list can expand and compress

[Alex Glaros]

Perhaps most jointly parented governmental organizations are functionally, collaborative "projects" (not organizations) which my model handles. But thanks to Laura, will not assume there are none, or will never be any in the future, so will use adjacent list (see fast response times documented in explainedextended.com article below), but created new 1:M table to handle multiple parents.

ORGANIZATION
-----------------------------
1. organization_Id (PK)
2. organization_name

ORGANIZATION_HIERARCHY (1:M)
------------------------------
1. organization_Id (FK to above table) - can have multiple parents
2. adjacent_parent_id (FK to above table) 

Thanks to all for the assistance.  Led me to some great articles including
http://explainextended.com/2009/09/24/adjacency-list-vs-nested-sets-postgresql/

Alex