Interesting windows networking situation

Interesting windows networking situation

I have 2 PC: 1 of them runs Windows 8, second Win XP SP3. Windows 8 PC
gets internet from A wifi network and shares it into internal network
created by itself (which consists of 2 pc's) via switch (lets call it
network B). It plays role of DHCP server: assigns ip to second computer.
in A network it has ip like 192.168.1.xx and in B network it has an ip
like 192.168.137.xx.
The question is.. I want to share something between B network devices.
Will this be visible to network A devices? I mean, is network B visible to
network A devices?