how to 2 channel 4 ohm amp at 2 ohm?

Hello. I have a two channel amp that outputs 100w x 2 at 4 Ohms, or 200w x 2 at 2 Ohms. I also have 2 single coil 150w subs at 4 Ohms. I know that if I run the subs in parallel I get 2 Ohms out of them. Is there a wire configuration that will make the amp output the 200w x 2 at 2 Ohms? Because if I run the single coil speakers in parallel I only have one positive and one negative wire.... The amp also runs 400 w x 1 at 4 Ohms bridged, and has the two speaker inputs. A+ B-          C+ D- What's the loudest configuration possible? Right now each sub is plugged directly, so the amp is outputting 100w to each 150w speaker at 4 Ohms. Thanks

The way you have it connected is the safest / best configuration possible.