I suspect the short answer is 'no, you can't do this'. There doesn't appear to be another overload of the Set method that would allow a mapping where no class field/property exists.The name of the string parameter - the one Fabio refers to - is 'notVisiblePropertyOrFieldName'. You are passing it the value of "LastWeekOrders" which is not an actual field/property on the class you are mapping - hence the MappingException.
I personally like to keep query/filter semantics out of mappings. Queries should be used for querying.
