Hi @praveen726,
Take a look at the below documentation on VA deployments. Any of the VA added in a VA cluster can take up the assigned task and you do not have any control on which VA should be assigned the task.
The document highlights the possibility of latency issues if you have VA’s of different location added in the same cluster for HA.
You can consider creating another VA cluster with VA’s residing only in (north colo) and assign it to your AD sources, if that solves your problem.