Script question

Hello all. I have a problem to solve, maybe you can help me.
The situation:
– one domain, two sites (subnets) – WAN link (slow one)
– each site has a DC which is the global catalog
– I use a startup script – kixtart – that is based on gateway recognition
Problem:
– even thought the script is based on gateway recognition, it applies over the WAN, from the first DC installed and not from the DC on the site.
– by replication, the script is also on the second DC.
Question:
– How can I make the script to be applied from the DC on each site, and not from the first DC in the domain?