I'd probably create calculations to get the total for each type like:
Type1Total = (([ItemType]==1)?[TotalPrice]:0)
Type2Total = (([ItemType]==1)?[TotalPrice]:0)
Type3Total = (([ItemType]==1)?[TotalPrice]:0)
Type4Total = (([ItemType]==1)?[TotalPrice]:0)
Then you could add rules based on the totals of each type individually.