Not sure there's any way to selectively take out Bermuda grass. When I took out our front lawn, lots of Bermuda grass tried to take back the space. It took dousing it with vinegar during sunny days, then digging out the grass at the roots to beat it back. It required weeks of steady effort but now hardly any comes back. Only every couple of months do I need to make a pass through the area to fend off incursions.

Also: why bother with any grass? We're much happier without a big green sponge out front. Our water usage is way down and the local wildlife likes the natives and our raised beds.