Found this document which seems to refer to 2010.
https://technet.microsoft.com/en-GB/library/bb123805%28v=exchg.141%29.aspx?f=255&MSPPError=-2147217396
What we want to do is create new distribution groups based on some legacy security groups. Would rather not just convert them just in case we lose security functionality. So plan is to create new ones.
But then we don't want two identical groups in exchange (although one could be hidden from GAL). Better if we could split the security group from exchange completely.
Will this work - doesnt really say if its just distribution groups :-
Disable-DistributionGroup -Identity "Employee Garage Sales".