Agree with Dan here. As long as the four inputs and typical balanced inputs with a 20k or so input impedance you will be fine with just a straight four way split.
What specific gear are you connecting?
You should be OK.
Back in the day, audio was a 600 Ohm matched system, with the o/p Z of the source matched to the input Z of the following stage to obtain maximum power transfer.
This made splitting complex.
A splitter amp terminated the previous stage correctly, took the input to the splitter via a high Z bridging input, then used individual o/p stages for each required output.
Modern practice is to have a very low o/p Z for the source & bridge across it with a high Z input ( around 20k or so as quoted).
Even a 600 Ohm input on the next stage is very, very, close to correct, but is about as low as you should go.
We used a low Z audio generator to feed the two 600 Ohm inputs of a TV Stereo sound exciter in parallel, & wondered why the FM deviation was a bit low.
When we did the Maths it was obvious---not much error in dBm, but a noticeable difference in voltage level, & hence, deviation.
TL/DR:- Yes, just hang them in parallel--- modern practice allows this.