Multiple users editing one powerpoint file

[Steve]

Is there any way that when preparing a presentation, more than one
person can edit a powerpoint file at the same time? This would be very
helpful as it would eliminate the need to repeatedly merge multiple
versions of the same presentation from different people as changes are
made

I can envisage this being done with a central 'master' file stored on
a network, and all the users working on copies of this, which can then
be used to update the master file regularly. There are obvious
problems if people make changes to the same slide simultaneously, but
has any clever person come up with a way round this?

thanks, Steve