Hi Sunny,
yes, such a dual, triple, etc. wireless microphone system could be an option if the receiver, in addition to the separate outputs for each microphone, also has a "mixed" output.
Please note, however, that you can then only control the volume of the individual microphones separately, not the sound. Usually you need different EQ settings for each singer, i.e. each microphone. And for this, as mentioned, you need an additional external Mixer.
Best regards,
Chris