ART SPLITMix4 4-Channel Passive Splitter/Mixer ARSM4 $100 - $250 There are also 1/4" main

There are also 1/4" main outputs and a 1/4" headphone jack for convenient monitoring

while sending the isolated output to a monitor

An included breakout cable supports four analog PWM radio remote control inputs

All ModMics feature a patented design that marries the performance of the microphone with features that optimize comfort and usability

This thing does the job

ART SPLITMix4 4-Channel Passive Splitter/Mixer ARSM4 $100 - $250 There are also 1/4" mainThe SPLITMix4 from ART is a passive hybrid mixer that can be configured for a variety of applications. The compact unit can mix 4 stereo inputs down to a single stereo output, split a single stereo input to 4 outputs, and more. The unit has 1 4" TRS input and output connectors, which can also accept mono TS connectors. Each channel has its own level control for convenient customization. The unit is entirely passive, so no batteries or power supply are