how to update two or more Entities with a single input form?

Hi..

Can any one tell me how to update two or more Entities with a single input form?

I have this application where a user named supervisor inputs a form, when he purchase a tool. He would input the form with the to name and tool category with price of the tool and the purchased date. The input form is for the "Expenses" entity. It should update the "Tools" entity too. 

The data should update the following entitities.

* The "Tools" Entity. ( a field for the tool name)

* The "Expenses" entity. ( a field for the tool name)

Can this be done??

Here is the domain model that I currently have.

Please help