Sorry for my terminology I am not proxy expert.
What I need to do is to have a very simple HTTP(S) proxy on one side without any client authentication (this is so that clients don't need to supply username/password to connect to it), while this same proxy needs to redirect everything to the next "real" proxy which does its magic.
Maybe someone can just point me in the right direction - perhaps just a few lines of Squid configuration (just to get an idea what to look for) would also be accepted as the answer.