Insert formula in pivot table

Hi Friends,

I have a pivot table that has "POST CODES". I will need to insert a column in the pivot table to show "STATES".
For this I will need do a calculated filed for "STATES"

All post codes are stored in text format (for eg-08000). I don't want to convert the text to number, keep it as it is

All postcodes beginning with 0 is NT state, 2 is NSW state- list below

0= NT
2=NSW
3=VIC
4=QLD
5=SA
6=WA
7=TAS

Can you please suggest a formula

Thanks

Any help please

I have attached a file, for easier understanding. Any help will be greatly appreciated

File attached

I was advised to use formula LOOKUP(LEFT(A2,1),{"0","2","3","4","5","6","7"},{"NT","NSW","VIC","QLD","SA","WA","TAS"})

But this formula will work only if I use it outside the pivot table. I will need a formula to be used in the "Calculated Field" of the Pivot table