Which is the best way to grant GrantSendOnBehalfTo to a SharedMailbox for multiple Users?

Hi there,

we have multiple AD Sites and on each Site one MultiRole Exchange 2010SP3 Server. I have a question, regarding GrantSendOnBehalf Right Management for Shared Mailboxes. 

First type/usage for SharedMailboxes:

Shared Mailbox and one GlobalSecurityGroup for FullAccess on SharedMailbox.

The Global Security Group contains each Member who needs access to the Mailbox and has the FullAccess Right of the SharedMailbox. 

Second type/usage for SharedMailboxes:

All Settings of the first type. 

Additionally 1 universal security Group, which contains the Members who need to send E-Mails outside the SharedMailbox. 

This Universal Group with Type "Security" has the right "GrantSendOnBehalfTo" of the SharedMailbox. 

This works fine.

But, i´m a bit confused, about the two "Group Types" which can be used in EMC. There are "Security" and "Distribution". Both types are working well in my situation. I can use the Type "Security" or "Distribution" for Managing the "GrantSendOnBehalf" Permission. 

If i compare two groups, one "Universal Distribution Group" and one "Universal Distribution Group, Security Enabled"

There are a few attributes which are different. 

GroupType --> Universal,SecurityEnabled / Universal

MemberDepartRestriction --> Closed/Open

RecipientType --> MailUniversalSecurityGroup/MailUniversalDistributionGroup

UMDtmfMap --> 

Can someone explain a best practice for my situation? 

Thanks in advance.