Prevent a state transition on checked out objects

Hi, is it possible to prevent a user from initiating a state trasition in Hubshare as long as the object is checked out?

We have discovered that if you try and send your object onward in the workflow while it is still checked out, the object will not leave your control, but it will show that it has entered the next step in the workflow. Once you check in the object it will transition, but the user still sees the object and has the means to continue working with it, although it is in a state where they should not be able to. If you reload the page the object will disappear from the view.  We have configured our Hubshare so it is used only by external users and each step in the workflow is a hand off to another person. If they can do other peoples work is a major issue for our client.

If you can't prevent the state transition from happening, is it possible to get an automatic refresh of the page once the object has been checked in and enters the next state?