[SQLObject] ViewSQLObject ID's

Hi,

I decided to try the ViewSQLObject class in an attempt to speed up my 
system by letting the server do some of the table joins in single queries,
instead of joining in python on the client side.

But I get stuck at the id.  I assume that ViewSQLObject objects
need an immutable and unique ID (is that right?).  All the examples 
I have seen just copies the ID from one of the constituent SQLObject-s. 
In my case I am joining on a many-to-many relationship, so I assume
I need to aggregate multiple ID fields into one.  Can anyone offer 
a quick example showing how this could be done?

TIA
-- 
:-- Hans Georg