Need help wiring a relay to do this...

Here is what i would do:

Parking light wire (+) -- Terminal 30

Headlight wire (+) -- Terminal 85

Ground (-) -- Terminal 86

Power to city lights (+) -- Terminal 87a

Terminal 87 -- No connection

No relay needed here

The city light bulbs have 2 wires...one  pos and one neg

take one wire and hook it up to the parking light positive....take the other wire and hook it up to the headlight low beam positive......the lights will turn on with parking lights and turn off when the low beams are on....true they will turn back on when the high beams are on....but you will never notice them.