I have a basic ms access question about a relationship between 3 tables

Question

I have 3 tables

1. ITEMS - PK = Item# - contains item details
2. ORDERS - PK = Order# - contains order summaries
3. TRANSACTIONS - PK = Transaction# - Contains a breakdown of multiple transactions that make up an order

They all have an Item# column.

I have a one-to-many relationship from items.item# to orders.item#.

My question is: should the relationship to Transactions be from Items.Item# to Transactions.Item#, or from Orders.order# to transactions.order#?

Thanks