Use imagecfg.exe to use 4 out of 8 cores

How can I set imagecfg.exe to use 4 out of 8 cores rather than an single core or all 8 cores.

To set a process's affinity use "imagecfg -a MASK [File Path] [File Name]

 CPU   MASK
  0    0x1
  1    0x2
  2    0x4
  3    0x8
  4    0x10
  5    0x20
  6    0x40
  7    0x80
  8    0x100

So if you wanted to set C:\Test\Dummy.exe to use the second CPU(CPU1) ir would look like this:
imagecfg -a 0x2 C:\Test\Dummy.exe

So would assigning more than one core look like this?
imagecfg -a 0x1 0x2 0x4 0x8 C:\Test\Dummy.exe