4 PCs all XP cannot all see each other?

Hi,

I have a small network. 4 computers(3 desktop, 1 laptop)I will call the computers a b and c. the laptop will be d. All are connected via CAT5 to a Linksys router. Router is connected to a cable Internet connection. All computers can browse Internet. All are using dynamic IP addressing. All have XP firewall turned off! All have Norton with firewall turned off! Computers A and D are XP pro. Computers B and C are XP home. All have file and print sharing installed. Now here is the problem. Computer A see computers B,C, and D. Computer B see Computer A & C only. Computer C see A & D, but not B. Computer D sees A & C only, but not B. Bottom line is I need A,C, and D to see Computer B because they is a common folder on that computer that all the other computers need to access on a daily basis.

Thank you for any help.