Not able to create same item template under two different item class

Summary:

Dear Experts,

We have a business scenario to create two different item classes due to security reason. Let's say Item Class A and Item Class B. However, same Item Template to be used for both item classes.

• Created two different Item Classes A and B under Root Item Class.
• In Class A, copied one of existing seeded Item Templates 'Purchased Item' to create a custom Item Template - Stocked Items.
• Tried repeating the same for Class B but system is throwing error and not allowing to create Item Template with same name - Stocked Items.

We are trying to achieve below structure but system is not allowing to create 'Stocked Items' template in both child item classes.