Can't reliably connect to network with 5 AEs config'd with 'extend network'

Question

To accommodate a large house, thick walls, and detached guest house I setup five airport Ex's using the 'extend network' option. One is connected to the cable modem and the other four extend. All four get green lights. I get good reception in most places but it appears that I often don't connect to the closest AE, even when only a few feet away. In some cases my signal will go from full to zero in the span of a few feet. The network is the all n/5Ghz mode.
When checking the logs of each of the AEs I found that I wasn't connecting to the closest unit and in the case of the farthest AE I never connected to it. When I stepped a few feet away from the farthest AE I lost all signal.
1. There's no relay or remote option when 'extending network'. Is there a way to force connection to a particular AE?
2. Is there a way to prioritize among the AEs? Like with networks.
The logs show three AEs connecting to the Main AE and the fifth one connecting to one of the the three relays. Is there a maximum daisy chain length?

Answer 1

I checked my 4 extremes and found that the 3 mac mini's, 2 powerbook's, 1 imac, and 1 xserve do connect to the closest extreme.
I have 1 extreme in the middle of the 2nd floor as the gateway. An extreme on the third floor for 2 mac mini's, an extreme on the far end of the second floor for an imac and a powerbook, and extreme on the 1st floor for a mac mini, powerbook, and xserve.
One item for consideration to help control access is by manipulating the min connect speed dialog box. The default is 1 mb. Up that number until your clients become ineligble to connect to distant routers. As cleints move away from routers, their connection speed reduces.