Code:
SWS: Select next region
SWS: Goto/select next marker/region
SWS/S&M: Go to/select region 1 (obeys smooth seek)
SWS/S&M: Go to/select region 2 (obeys smooth seek)
SWS/S&M: Go to/select region 3 (obeys smooth seek)
SWS/S&M: Go to/select region 4 (obeys smooth seek)
Either of those would probably do what you want. And if not, you can probably use them to create an action that does.