GroupAddressMembers Property

public InternetAddressList Members { get; }

Property Value

Represents the member addresses of the group. If the group address properly conforms to the internet standards, every group member should be of the MailboxAddress variety. When handling group addresses constructed by third-party software, it is possible for groups to contain members of the GroupAddress variety.

When constructing new messages, it is recommended that address groups not contain anything other than MailboxAddress members in order to comply with internet standards.

Reference