Linksys WRT54GS WRE54G - WEP keys question

Easy question for most of you.

I set up WEP 64 bit 10 hex security for my Linksys router and
separate Range Extender.

They both are set to use the same passkey/phrase and have the same
SSID.

This is in my house so I do not need a lot of security. Just keeping
others from freeloading on my WiFi, which is happening.

Question: 4 keys are generated and are the same on the router and the
Range Extender.

*****Can the same key be used by more than one wireless device
(laptop, TiVo, Squeezebox,etc)??

Or do I need to use key 1 for one device, key 2 for another ,etc..

Thanks so much
Patty