We try not to modify chat hook much, so no, there is no current way to do what you're asking within ULX.
The reason the guest user commands are never seen now is due to the fact we stop execution of the chat hook.
Once you go into actually modifying whether or not what is typed is seen or not based on rank, it can really complicate matters in the chat system, especially if there is another mod that monitors chat hooks in some way.
Over the years, our recommendation for not wanting to see commands issued is to use the game console, and/or XGUI.
Setting logEcho mode appropriately will also help.