There's not currently a way to do this.
The cf CLI actually chooses the default shared domain simply be being the
first in the list.
I've often thought about allowing an Org Manager/Space Manager to specify
a preferred default domain for the Org/Space.
This would of course require changes for the cf CLI and other clients to
respect that selction.
If you are very interested in this feature, I think a PR for this type of
enhancement would be fine.

-Dieu
CF CAPI PM

On Fri, Feb 19, 2016 at 11:33 AM, Stephen Byers <smbyers(a)gmail.com> wrote:

I have a shared domain that spans all orgs and is currently the default
domain used when I push an app. I have created a private domain in an org
that is specific for, say, integration. Is there a way to set the private
domain of a particular org to the default one that is used when none is
specified in the manifest? This would allows us to use the same manifest
but push to one org for a sandbox/dev area and another org from the CI
pipeline without having host collisions in the same Cloud Foundry
installation.

If there is another way I should be thinking about this, that is welcome
also.

Thanks in advance.