I have a bunch of nested e-mail distribution groups left over from when I upgraded to Exchange 2007 awhile ago...  Now I'm finding that some of the advanced features of Exchange 2007 require them to be "Universal Groups" instead.  I was able to convert a bunch of them, but I still have an awful lot of "nested" groups that won't convert.    In other words, Exchange won't convert the parent group because it has non-universal members, and won't convert the members because the parent group is a non-universal group, a proverbial Catch-22.

So, since these groups are in constant use, I cannot remove the members, convert them and re-create the groups fast enough to not cause disruption.  Is there a way via PowerShell that I can convert them quickly?