I would contact the ARRL before I would make a investment like that..
There is a pretty good chance that what you are talking about is not legal.
I don't know if those phones are Part 97 approved and I am not sure if spread spectrum or digital phone is legal - because of the way it might be scrambled being a phone and all.
Second problem is that in order for any type of communications to work - you need to have two radios on the same frequency and I highly doubt that in a emergency you are going to find people operating on 900 mHz..

As a matter of fact, unless you are in a big metropolitan area - you probably won't even hear anyone operating on 220 MHz anymore..

Most Technician's are relegated to two meters phone - due to the fact that most walkie talkies are two meters and the cheapest mobile radios are two meters only..

Even just getting someone to buy a dual band transceiver or better equipment is like pulling teeth...

Like I tell all perspective hams - get a license and join a real ham radio club and LEARN... Find a Elmer - don't think that you can do it on your own..