We have universal security groups in AD where one group is the member of the other. For top level groups It can go 3-4 levels down to the group with recipients in it. If I create Distribution Group in Exchange 2010 EMC for only top level AD security group the group is not expanded in Outlook and no emails is sent. I have to create the Distribution Groups in Exchange EMC for all the chain of AD groups in order for the top level group to expand to the recipient level. Is it by design? Can"t Exchange 2010 just use AD to expand multi-level embedded groups? I do not want to replicate AD group structure in Exchange..