|"Server and laptop are on differents networks."|
Not possible unless you setup a VPN connection or a Router to connect the networks. You can not talk to computers on different networks.
If they where on the same network then you could just write a loop that would go through all of the IPs for the laptops and do a copy to the UNC path. Need to know what subnet they are on but assuming it is 255.255.255.0, on a 192.168.1.x network, and assuming the laptops are 100-125 then...
FOR %%A IN (100 101 102 103) DO (
COPY \\YOURSERVER\YOURSHARE\YOURFILE.TXT \\192.168.1.%%A\COMPUTERFOLDER\YOURFILE.TXT
This is also assuming the computers are on and the COMPUTERFOLDER has got a workgroup share setup on it and the user you are logged in as has rights to that share.