Refusing New Connections as well as New Instances

We have an app that is deployed that is both session based and direct
action based.  When a new version of this app needs to be launched I
refuse new sessions via Monitor and wait for the instances to stop.
Occasionally an instance will stay alive and create new sessions, even
with it refusing new ones.  We believe it's caused a visitor who hits
a direct action to a refusing instance who then is able to create a
session.

Is it possible to refuse both new sessions and new connections to an
instance while still allowing established sessions to continue making
connections?

Deployed on WebObjects 5.2 on MacOSX.
-- 
Ken Schweigert, Network Administrator
Byte Productions, LLC
http://www.byte-productions.com