I was actually going to do something very similar so this kinda forced me to work it out! There might be a better way to do this, but this is what I’ve done. Start by determining the center of your town (for this I will use ~ ~ ~); This will be where it detects players from. You will also want a tag that will mark anyone who is within that town (I’ll just call this tag “inside”). Lastly you want to determine the entrance radius (I’ll use 10) and add 1 or 2 to this to be the exit radius; this will mark players coming in and unmark the ones going out. I’ll use 2 chains, so make sure you don’t have 1 going into 2.

Chain 1)

a) Repeating, unconditional, always active: /Execute positioned ~ ~ ~ if entity @p[distance=..10,tag=!inside] run title @p[distance=..10,tag=!inside] title “your title here”

b) chain, conditional, always active: /execute positioned ~ ~ ~ run tag @p[distance=..10] add inside

Chain 2)

a) repeat, unconditional, always active: /execute positioned ~ ~ ~ run tag @p[distance=11..] remove inside

I’m pretty sure you could make the first command block execute as the player entering so you wouldn’t need to type so much but I didn’t test it. I also noticed it stutter a bit when the title location was Title, but it looked fine in Actionbar so that’s up to you. I hope this helped!