Just a suggestion, why not use PTT instead of walkie talkie. I think they have daily subscription rate of RM1 per day. Can use that during convoy....

Not sure how good is the coverage area though...........

Maxis PTT Url Link

Is it compatible with all phones or just certain models? I'm just afraid that my basic phone doesn't have the feature

Only phones with the PTT feature.

IMO This is not a preferred mtehod because there are only a few PTT phones there and people have to buy extra phone. It's also subject to Maxis data coverage area which is not good. Also you need to configure who can receive ur ptt which is troublesome when in big group. Talkie just press and all units unlimited in range can listen.

for maxis thing, can ask zen....
zen y my area always drop call ar??? pj sunway ss2