To answer your question, Robosapiens and Robopets work using IR (Infra-Red) technology and not RC (Radio-Controlled). IR is the same technology that television remote controls use.
Between robots of different type (ex: between a Roboraptor and a Robosapien) there is no conflict because the remotes use different frequencies. However, with robots of the same type (which I gather is applicable to you), there are conflicts. BUT, your grandchildren may still use their robots together because of the nature of IR technology. IR uses line-of-sight; you just have to point the remote at the robot that you want to control. Who knows, maybe it can become a game for kids.
I hope this answers your question. If you would like to know anything else, feel free to ask.
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