Hopefully more simple than im making it: Text effect question/trk matte question

This is definitely something I should've learned by now. I have some shapes that I want to move over/under some text. I want to achieve a look where the bits of text covered by the shapes becomes the same colour as the bg. So far all I have been able to do with fiddling with the trk mats is that it does this but only shows the text that is covered by the shape. I feel like this should be relatively simple and I'm just being dense. Am currently doing some googling now but thought it worth posting here as well. So if you have a solution or know of a guide/video that can talk me through this I would be greatly appreciated. Here's a pic for clarity