link common slides in multiple presentations

[robtho]

I have 8 common slides that I use in over 20 different presentations and from time to time the information in the common slides needs updating.
How can I link the presentations so that I only need to update the information on a common slide in one presentation and it then automatically updates on all of the presentations?


Any help with this will be great as it's one of those things that costs me many hours.