There is a great article about configuring multiple package internal package repositories here. However, if you are looking to configure these behind an Apache proxy, you may have trouble. I certainly did.
The issue boiled down to Apache not wanting to allow encoded slashes by default. This resulted in Apache discarding the requests from pkg rather than passing them on to the pig-depot server. The fix was to add AllowEncodedSlashes NoDecode to the httpd.conf file:
ProxyPass /s11Repo11_1_20_5_0 http://localhost:10082 nocanon
ProxyPassReverse /s11Repo11_1_20_5_0 http://localhost:10082