Help reading DP4T slide switch schematic
The black part slides in to any of 4 different positions, making connections as follows.

Pos A: 1 to 2 and 6 to 7

Pos B: 2 to 3 and 7 to 8

Pos C: 3 to 4 and 8 to 9

Pos D: 4 to 5 and 9 to 10

So, it looks like some Boolean algebra needs to be worked out to achieve at best a single pole 4 throw switch.

Is enough for your purposes?  You might want to go to a different type of switch.  From what I see, the manufacture called it a DP4T switch, but it's really a 4 position slide switch with sequential contacts.