You can't connect everything in parallel, so the next way would be:
Parallel a 4R with a 2R. Connect them in series with another 4R paralleled with a 2R, giving 8/3 ohms.
The other way would be:
Parallel the two 2R, and connect in series with the two parallel 4R. The result would be 3R.
One of these methods would work better than the other, depending on the drivers.