how to assign primary key or unique constraint to pre-existing index?

Hi, this is probably a FAQ: is there any way to tell pgsql to
use a specific preexising index for PK or UNIQUE constraints
instead of creating a new one?

-Gunther


--
Gunther Schadow, M.D., Ph.D.                    gschadow@regenstrief.org
Medical Information Scientist      Regenstrief Institute for Health Care
Adjunct Assistant Professor        Indiana University School of Medicine
tel:1(317)630-7960                         http://aurora.regenstrief.org