Hi,
There are no API available to automate or allow bulk search. That being said, you can narrow down your search using a wildcard, such as *@domain.com to search all users from a particular domain. Additionally, not all fields have to be filled in the search. You can specify the sender, but keep the recipient blank, and have the search delivered via email so you can apply search filters using a program such as Excel so that you can re-arrange the data. YOu can review the below help article for more details.
http://help.symanteccloud.com/Symhelp/Home.aspx/Default?localeId=EN_US&topicId=v54062069_v53994939&prodId=MLEMTT