G'Day tlc,

There are a number of options, of which two are as follows:

1. Create Distribution Lists by Company.

2. Begin in Contacts. Make sure that you can see the Folder List.
   Create a New View with Group By Company.
   use SHIFT+Click, CTRL+Click and CTRL+A to select some/all
   of the Contacts in view. Drag the selection and Drop on the Inbox
   Folder - you will get a New E-mail Form addressed to the
   selected Contacts.

You can address the messages from the contacts folder itself.  Switch to or
create a view that sorts in the way you want, select the contacts to send the
message to (hold down CTRL while clicking to select multiple contacts), then
click the Actions menu and choose "New message to contact".  When the new
message form comes up, all the contacts you selected will appear in the To
field.

You can change the sort order in your contacts to be sorted by the 'file as'
field, with the following steps

Sort the Contacts list by the File As field
Start Outlook.
On the Tools menu, click E-mail accounts.
Click View or change existing directories or address books, and then click
Next.
Click Outlook Address Book, and then click Change.
Under Outlook Address Books, click Contacts: Mailbox - YourMailboxName, and
then under Show names by, click File As (Smith, John).
Click Close, and then click Finish.
Verify that the newly created contacts are filed in last name, first name
order
On the Tools menu, click Options.
Click the Preferences tab, and then click Contact Options.
In the Default "File As" order list, click Last, First.
Click OK twice.
To view the new Contacts list sort order, restart Outlook.
Note  If you want to display a particular contact in a different order than
the rest of the Contact list, you can modify the File As field in individual
contact cards. For example, you may want to sort some contacts by the Company
field.

http://office.microsoft.com/en-us/assistance/HA010565141033.aspx