Please explain your feature request to the best of your abilities:

/t bantown would ban all members belonging to a specific city

example:
/t bantown Florida

all florida members would be banned from the city

Not sure what you mean by banned from the city.

https://github.com/TownyAdvanced/Towny#a-special-message-from-llmdl-precedes-the-normal-readme-

add all the city members to the outlaw list

like /t trustcity

Duplicate of #6544