Delete ALL snapshots except current?

I have a Parallels 9 VM with about a dozen snapshots with various versions of software installed, and multiple branches - very useful.

Unfortunately I need to expand the HD in order to install Office 2013 (it just won't install with the auto expanding HD and needs more space than is available) so I need to delete the snapshots.

So, do I really have to delete them one by one - I can't seem to say "roll up into the current snapshot" or similar..

J