I want to make a combination of drop down lists like below in Excel. Please help! Thanks

Scenario1 -
In Cell A1 (drop down of Main list): I choose "Item A".
In Cell B1: I can choose "Upper Part I" or "Upper Part II" which is Sub list#1 for Item A.
In Cell C1: I can choose "Lower part I" or "Lower part II" which is Sub list#2 for Item A.

Scenario2 -
In Cell A1 (drop down of Main list): I choose "Item B".
In Cell B1: I can choose "Upper Part K" or "Upper Part J" which is Sub list#1 for Item B.
In Cell C1: I can choose "Lower Part P" or "Lower Part Q" which is Sub list#2 for Item B.


Main list:
Item A
Item B

Sub list#1 for Item A:
Upper Part I
Upper Part II

Sub list#2 for Item A:
Lower Part I
Lower Part II

Sub list#1 for Item B:
Upper Part K
Upper Park J

Sub list#2 for item B:
Lower Part P
Lower Part Q