Are you looking for DiskLess Booting on the TWO Client Systems (p4) using the MAIN System as Source (Dual Core) -and those Client Systems that will indeed Share INTERNET once Booted using NETWORK ??? If so --- Follow below mentioned links
Diskless Windows XP over iSCSI - YouTube
Windows Diskless with AoE | A definitive guide to how to boot Windows Diskless with ATA over Ethernet Protocol (AoE)