Tire Blowout problems of the 1996 Chevrolet Tahoe

I purchased 5 toyo proxies 285/60/18 and have had a blow out on the side wall of two within the last year with premature cracking on all of the tires. The first tire that blew out I thought was just an accident. But after purchasing the 5th tire and then having a blow out on 4/2/2008, within 6 mos of them, where the sidewall was affected, I decided to look online and found where the proxies were having issues with other consumers with blowing out the sidewalls. Co wanted a four wheel drive business that deals with their product and have them inspected. They were inspected and showed the tire depth, premature cracking, etc. After having them inspected, business condemned the tires tire manf then decided that they had to have the tires back before they would issue any warranty or prorating on them. Did say that they would issue a prorate of 78% on each tire, but I had to send the tires to them via ups which they would pick up the cost of having the tires shipped up to them. As I explained I had no problem sending the tires as in good conscience, I could not sale these tires to anyone else as being in this field for 13 years and knowing the safety issues regarding tires having these issues, I did not feel that they were safe for anyone to have on their vehicles. Ups picked up the tires and after a few phone calls I finally received a letter from tire CO stating that they were not going to warranty or prorate the tire as they did not see anything wrong with them. I travel the interstate quite a bit and after having two of the sidewalls blow out as they did I was very fortunate that I didn't cause a severe accident and I would consider this to be a safety hazard for interstate travelers at high rates of speed. This is something as a consumer, that I feel should be looked into more closely as it could cause a serious accident.

While traveling at 25 mph rear tires blewout. Please provide further information.