Now I'm confused.
You have two guest hosts on esxi, one of them being the pf.
And you have full admin access on the guests.
So you can change the default gw on host1 to point to pf lan on host2.
I suspect these two are on the same bridge or other common interface.
As for the rest of the network, you can route eg all rfc1918 ip space to original default gw and keep everybody at bay.
Perhaps I'm missing something here. Please elaborate.