Dont worry about the subnets for now. Just post the output of each of the commands. Letting us know which PC is which. We will be able to tell you if they're on the same subnet.
You will need to do these on each PC to see if one is causing the problem.
Press [Windows] + [R], type services.msc and press [Enter].
Check the following services are running:
HomeGroup Listener, HomeGroup Provider, Peer Name Resolution Protocol, Peer Networking Grouping and Peer Networking Identity Manager.
Public Folder sharing options:
Click on the Computer Icon in taskmanger and select Network and Sharing Center
Click "Change advanced sharing settings" in the Network and Sharing Center – expand "Home or Work", scroll down and verify that both Network Discovery and "Public Folder sharing" are On
Check your network type:
HomeGroups will only work on networks designated as Home not Public or Work. Verify this on each PC by opening the Network and Sharing Center – if necessary, click the link under the network name and select Home.
Your PCs needs IPv6 enabled in order to connect to a HomeGroup: from the Network and Sharing Center click "Change Adapter Settings", right-click your network adapter and choose Properties, then verify the TCP/IPv6 entry is ticked.