Problem with releasing module licenses on network dongle

We have a custom setup where we store, in a dongle feature, the number of users allowed and number of currently available licences per module in the application.  If the users PC loses connection to the network then the licence that is recorded, in the dongle feature, as taken for that module by that user is never updated again as being released.  We need a way to link the PC/heartbeat to the module licences that have been taken so that if the heartbeat dies without the module licences being released they can be reset after some time out.

Do you have any suggestions for how we can achieve this?

Thanks