I'd need to know more about your events to give you a complete answer.
Here's my interpretation and solution.
PCs come into town for first time and go to a particular place. They're greeted by an NPC who tells them a fact or two about the city. He then tells them that he has stuff to sell if they are interested. He lets them know that they are welcome any time, but he's only open from sun-up to sun-down so that he can spend some quality time with his wife and not work all of the time.
It would be as follows:
Text event (triggers always, do event only once checked)(chain trigger is always)
Shop event (triggers daytime)(chain trigger is only if event doesn't happen)
Text event (triggers always) set to back-up one step on exit.
If you want to add another event to the chain, it's placement depends on what you want to do, and how you want it to depend on the other events.
In my earlier post, I wasn't meaning to add a quest event in your chain, but to use the quest as a trigger.