How to dynamically remove unpingable "A" records and add when host becomes pingable

[stevehunter_1 at hotmail.com]

Does anyone have a script or software they use so that I can
automatically update my "A" records when a host is unavailable.

i.e.
www.mywebserver.com has 2 IP addresses (A records): 1.1.1.1, 2.2.2.2

When 2.2.2.2 becomes unpingable, I would like to remove it's "A"
record so it is only 1.1.1.1
When 2.2.2.2 is again pingable, I would like to add it back to the "A"
records.

I have done extensive search for this and can not find anything of
value.  I am sure thousands of people are doing this, but how?  Can
someone send me a script or program?  Prefer something simple to use,
I do not have many domains (about 25) and perhaps a total of 150 "A"
records, but I need something automated.  Some cron or task that runs
every minute or every few minutes.  Thanks.