In general, as part of building the preOS, if the network adapter being used by the machine to talk to the GSS server has a static IP setting on it then that setting should get propagated into the preOS.

That process is pretty simple and thus robust if the preOS is DOS since only a single network interface is brought up. For Windows PE it's potentially more complicated ensuring that the settings from host OS get applied to the right network adapter, since Windows tries to detect all the hardware and; the Virtual Partition building code is set up to edit the unattend.xml file inside Windows PE to propagate static IP settings from the host OS into the preOS and apply it to the same network adapter.

So, provided that your machines acting as DHCP servers have a static IP address set on the network interface on which they communicate to the GSS console, in principle that network address should be what is picked up in the preOS. If that doesn't happen, then in the preOS the first port of call is the wattcp.cfg or unattend.xml file in which the static IP settings would be being passed down to the preOS.