Can squid supply user/pass for parent proxy?

I have set up a squid based proxy for a small group of users. These users should
NOT be queried for a username and password (ie they can't do basic authentication)
but our main proxy requires authentication.

I know it would be easy to configure the primary proxy to not require authentication
for this child proxy... but that is not possible.

Can I make the child proxy supply the required auth details?

Cheers
--Paul