Have trouble to build a visitor segment of include certain criteria in one time period and exclude another segment iOn the 2nd time period

I want compare 2 groups of visitor:

A-Ordered product: 1or2or3 in time period 1(say Aug.10th-Aug.25th) AND then ordered product: 4or5or6 in time period 2(say Aug.26th-Sep.5th)

B-Ordered product: 4or5or6 in time period 2(say Aug.26th-Sep.5th) But Did Not order 1or2or3 in time period 1(say Aug.10th-Aug.25th) 

I created below segments:

for supporting segment:

segment#1-Visitor level: in a hit container Order exist and Product = 1or2or3, custom time period 1

segment#2-Visitor level: in a hit container Order exist and Product = 4or5or6, custom time period 2

for final segment:

(for group A)segment#3-segment#1 And segment#2

(for group B,)segment#4-segment#2 And exclude segment#1

result: I can get a number of Unique Visitors for segment #3; but for segment#4, it is the same as segment#2.

How can I have number for segment#4 that is segment#2-segment#3?

Thanks a lot!