wi fi - How can I tell my device to ignore a public Wi-Fi network?

The city I live in has city-wide Wi-Fi available for a subscription, but the Wi-Fi access point is public.

This means that everywhere I go in the city I get a notice that there is public Wi-Fi available even though I can't use it because I don't have an account with the city-wide Wi-Fi service.

How can I tell my phone (Droid X, Android 2.2.1, not rooted) to ignore Wi-Fi named "CityWifi"?

I'd like to get notification for other Wi-Fi networks, just not "CityWifi"