One possibility could be to deploy a PAC file into Internet Options on each of the suite workstations, and use the timeRange() function to specify a "fake" proxy for a period covering the lunch break, and to go out directly (or specify your real proxy, if you use one) for the rest of the day.
PAC Functions | FindProxyForURL (expand the timeRange() entry)
For example:
function FindProxyForURL(url, host) {
// Lunch break is 1200hrs to 1300hrs (for example), so return a dead address during this time
// 127.0.0.1 loops back web requests to localhost, thus causing the browser to error out
if (timeRange(12, 13)) return "PROXY 127.0.0.1:8080";
else return "DIRECT";
}
Or if you have a real proxy server:
function FindProxyForURL(url, host) {
// Lunch break is 1200hrs to 1300hrs (for example), so return a dead address during this time
if (timeRange(12, 13)) return "PROXY 127.0.0.1:8080";
else return "PROXY my.real.proxy:8080";
}