How can i make a frequency dependent switch?
So, sounds like a bandpass filter, followed by a power detector. Detection can be as  easy as a diode rectifier followed by a simple RC lowpass. Feed that into a transistor as switch. Amplification might be necessary at some step.
Sorry that it's not more specific than that, but you probably know that in  RF engineering, things very much depend on the actual frequency range you work at, and since you've not given that, you are probably just looking for a general approach.