Hi, My name is Eric Moyers. I am a Network Support Engineer in the Cisco Small Business Support Center. Thank you for using the Cisco Community Post Forums.
Yes you can do that. Are you planning to use these devices wirelessly or have them hardwired back to the router?
If you use four, you can set one up as AP, and the other three as WDS Repeater to repeat the one signal.
If you purchase three, then one as main and two as WDS Repeater.
Once you buy them, you can call into the Support Center if you have any issues with the setup and one of our answering agents can help you.
Thanks
Eric Moyers
Cisco Network Support Engineer
CCNA, CCNA-Wireless
1-866-606-1866