Simple answer - Yes.
Firstly the air terminals need to have shared parameters governing the dimensions you want to tag. Currently OOTB families have family parameters which only appear in the properties palette.
Secondly you then need to add the same shared parameters from the same shared parameters file you used for the air terminal to an Air terminal tag family. Take an existing OOTB tag and edit the labels by loading in the shared parameters and then adding them to the tag. To make it look like you want you will need to have 2 Shared parameters separated the 'x' as either a suffix or prefix to one of the labels.
Once you have done these changes, load the families into the project and off you go. The shard parameters will also be available for scheduling should you wish to make an Air Terminal Schedule.
If you need further information downlaod the Autodesk document from this link:-
http://usa.autodesk.com/adsk/servlet/item?siteID=123112&id=13376617
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