2 transmitters/one vehicle

[sapper_triple6]

I bought my 3y/o a stampede xl-5. On the half speed he can control it fairly well but still occasionally runs into everything. I usually make him keep the antenna down all the way so he cant drive off very far. If I get a transmitter on the same freq. with the antenna up,will it overpower his so I can take control of his truck if I need to?