Hi Kevin,
Absolutely, it's possible, but it involves building your own chat UI (which really, is a TextInput and an EmoticonTextArea, so no big deal). Have a look at the examples folder of the SDK, under "SimpleChat". This sets up a SimpleChatModel (essentially, all that you need to chat, minus UI), builds some UI around it, and listens for the HISTORY_CHANGE event to update the UI when new messages are received. In your case, you can intercept any new chat messages and apply whatever filtering you'd like, before sending them to whatever UI you're using.
hope that helps.
nigel