Here’s how you can do it:

w32tm /config /syncfromflags:manual /manualpeerlist:<peerlist>

Official definition for <peer> follows:

manualpeerlist:<peers> - sets the manual peer list to , which is a space-delimited list of DNS and/or IP addresses. When specifying multiple peers, this switch must be enclosed in quotes.

So it should be very much like the following:

w32tm /config /syncfromflags:manual "/manualpeerlist:64.90.182.55 129.6.15.28 129.6.15.29 64.236.96.53 206.246.122.250"

If you are wondering where I took all those IPs, here’s the link. Or find a better one with google.