This particular rule will move all mail with a subject that contains the word [BULK] to your Junk Mail folder.
First open Groupwise and in the Toolbar at the top of the screen choose 'Tools' then 'Rules'.

After choosing 'Rules' the following box will appear. Choose the new button.

Enter the name of the rule in the box that says 'Rule name'. You may call the rule whatever you like, I called my rule 'SPAM Killer'. Under the heading 'When event is' make sure the 'Recieved' box is checked, see below for screenshot. Under the heading 'Item Types' check the box that says 'Mail', see screenshot below. Now select the button that says 'Define Conditions'.

The following box will then appear. From the first drop down menu select subject. In the next box, type [BULK] and then click OK, see example.

Now click the 'Add Action' button and choose 'Move to Folder'.

In the 'Move to Folder' dialog box choose the folder that you would like to have the spam moved to. 'Junk Mail' is usually the best choice. When you have chosen the folder, click the 'Move' button.

Now click the 'Save' button and you are done. Note: If you want to 'Run' the rule on all the email currently in your 'Inbox', just click the 'Run' button as shown in the screen below.

Final Note: You may want to periodicly check your 'Junk Mail' folder to make sure there are no valid emails that were marked as [BULK].