Sad to say not in FileMaster IMS 9.1.
New to FileMaster IMS 10.0 though:
IMS Editor Timeout
With this new safety feature, when you walk away from an IMS edit session, you won’t need to be concerned about the impact of a TSO session timeout while you're still connected to the database. CA File Master Plus for IMS will gracefully terminate the session just moments before the TSO session times out, discarding any uncommitted changes and preventing any adverse impact on the IMS region that might hinder productivity.
If you upgrade to 10.0 you will be able to take advantage of this.