[squid-users] Authentification on each multiple outgoing ip

Hi guys.
I have such issue. My head has already swolen from this issue ))) So...

I have server with several outgoing IPs. My task: to each outgoing IP
on proxy bind login-password

Doesnt matter ip source of user. User use proxy if he knows
login-password for separate ip on proxy.

i attach my squid.cong file.

so far, in squid.cong i wrote 2 proxy IPs.
i tried to bind different login-passw to them.
but.
doesnt matter via what proxy ip i want to connect my browser.
i setup browser even on IPs that not yet mentioned in squid.conf (in
squid.conf there only 6.1.9.1 and 2.5.2.4)
all the proxy IPs while trying to connect through them demand
login-password. And for all of them the only right login is mechelen
(see in squid.conf)

can anybody help with this task?
thx a lot!