Vista - Two Computers Can't See Each Other

I have a home network with 3 computers. The one in the office runs Vista Business, the one in the bedroom runs Vista Home Premium, and my laptop runs Vista Ultimate (all 32bit). They are all on the same workgroup. The office desktop can see my laptop. The bedroom desktop can also see my laptop. The office and bedroom desktops can't see each other. This is going off the window I see when I go to Start>Network. If I type in the IP of each computer manually, the laptop cannot access either desktop. Both desktops can access the laptop, however.

The main problem this causes is that I can't share the USB printer attached to the bedroom desktop with the office desktop, and I can't share the USB printer attached to the office desktop with the bedroom desktop. Since one of those printers is a color printer, and the other is a laser printer, this becomes really annoying. I can't even just share the files I need to print...I have to either email them to myself, or I have to pull out a flash drive.

What is going on? I actually like Vista, but the network problems suck. I had the beta on my laptop, and then the real one for a while, but went back to XP until SP1 came out because I couldn't deal with the constant disconnects. Now that's pretty much fixed, but random other problems still survive (like this one, and the thing with the network icon showing Local Only even though I can access the internet just fine).