How can email sender be overrided?

My requirement is to send out email campaign using account manager email. so email sender is different for each campaign email if their account managers are different.

Two ways to solve this I wondered:

(1) overriding sender email  based on its account manager email during campaign execution

(2) automatic process to create a campaign element for each account manager and also set up target group which belonged to a specific account manager

What is the workable solution in our CRM 7.0 enh pack2 environment? I cannot find any way to do it in way(1). Please give me some insight.

Thanks