Trying to remove shirt from men's suit

Hi there!

I've been making recolors of base game cc for a little bit but I'm still fairly new to meshing. I hope this makes sense, but I've been trying to make the top of a male formal suit that is open and doesn't have anything underneath it. So a shirtless open suit jacket. I took one of the base top formal suits that's dark grey with a black shirt underneath it and worked on the recolor. I deleted the inner shirt it came with and then applied it to the mesh in the Sims 4 studio program. However, on the mesh where the shirt should be is just white. I want it to be completely clear where you can see the sim's chest. I don't want it transparent. So on blender I tried to delete the mesh for the chest but then it was just a hole that you could see through the sim when imported on Sims 4 studio. I tried to move the mesh on the UV map but I can't delete or move them.

I've seen cc where it's just an open jacket with nothing underneath it and you could see the sim's chest but I don't know how it was done. Could someone help me with this please? If there's already a tutorial or post that covers this please link me to it. Any help will be well appreciated!

Thank you!