Look@Lan cant see some of my comps

[d3fc0n5]

well guys title says it all. look@lan cant see all of my computers. could the problem be that the comps it isnt seening are behind a router. Ive go my Lan setup like this
Cable modem--> Linksys WRT54G--->Two Comps--> Off linksys Goes to an linksys BEFW11S4--> three other comps....... the last three comps arent being seen by either of the first computers

Thanks