That cabinet has a nominal impedance of 4Ω so they are likely either 32Ω or 8Ω each. If they are 32Ω then all eight are wired in parallel and each group of four will be 8Ω. If they are 8Ω then there are two groups of four in a series-parallel configuration and each group is 8Ω. Either way, you will have two groups of four at 8Ω each.
No, resistance is not futile. It is voltage divided by current.