I've give you some things to look at but without more information diagnosing is going to be difficult.  First, are you sure you are not using the same IP address on multiple radios?  Second, you have a lot of power broadcasting in a small area and since you are using M2 devices and Picostations I know that they are all on the 2.4ghz spectrum.  Have you done any channel separation to reduce interference.  The 2.4 spectrum only has three usable channels (1,6,11) without overlapping.  Another thing to check is that you don't have any typos in your IP, subnets, and/or gateway addresses.  The gateway should be that of your main router.