How to change multivalued properties on Exchange 2010 (SP1,SP2) ?

In my case I wanted to change (add) trusted domains (senders) of Junk mail filter settings for members of distribution group. Set-MailboxJunkEmailconfiguration is the cmdlet for adding (changing) trusted senders and domain for user's outlook safe senders list. TrustedSendersAndDomains is multivalued property and values can be added or removed using following simple syntax without overwriting already populated values:

get-DistributionGroupMember -identity "alias" | Set-MailboxJunkEmailConfiguration -TrustedSendersAndDomains @{Add='emailaddress@domain.name','domain2.name', ...}

get-DistributionGroupMember -identity "alias" | Set-MailboxJunkEmailConfiguration -TrustedSendersAndDomains @{Remove='emailaddress@domain.name','domain2.name',....}

This syntax can be used for changing any multivalued properties not just TrustedSendersAndDomains property.