One way is to create another field next to description specifically for process owners. Navigate to Tools > Options > Descriptions. In the left part of this window you can create a new field and name it Process Owners. Drag the created field to the right part of the window and drop it on the models node. Click the plus sign to ensure that both Description and Process Owners are now connected to models.

Open the properties dialog for a model. Under Descriptions there should now be two tabs, Description and Process Owners.

The last step is to make sure that the information is included when publishing to HTML. When editing the HTML profile, in the Models category, make sure that Descriptions is included in the list named Fields. Otherwise add it to the list with the plus sign.