mail send on behalf to "out of office turned on" user issue

I am deligate for user A and sending mail to many users. Few user i send mails on behalf of A has their out of office on, and i am getting few of these out of office in my mail box while user A also is getting few. why is this happening? how can i set that only it "out of office" can come to me?

We have exchange 2003 and outlook 2007 in the environment.