Entity match for NULL

It should be possible in groups, or alerts for that matter to match NULL fields in database.

Let's say you want to create a group called "Ports with no ifAlias".

device match; os match procurve
entity match;
ifAdminStatus equals up
ifOperStatus equals up
ifType notequals ieee8023adLag
ifType notequals propVirtual
ifType notequals propMultiplexor
ifAlias isnull (or here maybe ifAlias match/equals NULL, but that will be a problem if alias is actually NULL )

Should be an easy one I think. Have some ideas I will try..