Derived table with SQL that references other view dimensions?

[sourdzl]

I am trying to create a new view which is derived from existing tables/views that are already specified in Looker.

In the “sql” value, I am able to do ${existing_view.SQL_TABLE_NAME} to reference that underlying table, however I am unable to do things like 

SELECT {existing_view.existing_dimension}

according to the lookml validation, as it results in 

Unknown substitution parameter 'existing_view.existing_dimension' inside ${}.

Is there anyway to also reuse those columns, so that we don’t have to manually update things in the derived table when the base table changes?