DB_DataObject: Nested joins possible with joinAdd()?

It seems to me that it's not possible to construct nested or chained joins with joinAdd(). That is, something like: select stuff from table_a left join table_b on table_a.b_id = table_b.b_id left join table_c on table_b.c_id = table_c.c_id I can't come up with a way to do this using joinAdd(), since it seems one of the joined tables always must be the current object, and in this example, neither of the tables in the second join is the current table/object calling joinAdd(), in this case DataObjects_Table_a. Will I have to use query() for this? Just wanted to check with those more knowledgeable than me before giving up. Thanks in advance, Andy