Looking for indicator based on NY Close

Hi Guys,

I am trying to write an indicator that alerts when the NY close was not re-visited in the next Euro/London session.

Any help with this would be great, or does anyone know how to program this?

without checking for holidays, easter, etc.:

one way would be to let the user input the servertime of the ny-close. so we could check the close of the corresponding h1 candle, compare it with the price until now and give the alerts.

You said you are trying to write an indicator for that. You could upload it and maybe someone helps you with the stuff