Add additional mics on the vocopro gigman all in...

Question

Hello, I would like to add two addtional mics fora total of four on my karaoke machine & I am not sure how to do so. My machine has 2 XLR mic inputs and 2 1/4 in jack mic inputs, however the manual states that both cannot be used simultaneously. Is it safe to simply purchase a spliter for each 1/4 inch mic jack , thus having 2 mics per 1/4 in micinput? Can you offer nay other solutions.

Thanks