No, GlassFish does not currently support a configuration with multiple
DAS cooperating in this way.
However, if the DAS crashes, the full cluster doesn't collapse. With
GlassFish 3.1, if the DAS is not running, the instances can continue to
run, and instances can even restart without the DAS being there. So the
application stays up. While the DAS is unavailable, it isn't possible
to do administration on the application, but normal operation of the
application continues.
Tom