Conditional for time of day schedules

Add conditionals for time of day schedules so that a schedule is only valid if a custom property is configured a certain way. For example, we have production nodes that we want alerts for 24x7x365, but we also have non-production nodes that we only want alerts for M-F 8am-5pm. We have created a custom property called "AlertWindow" which we set to either "24x7" or "M-F8-5", but in order to provide the same type of alerts for both production and non-production nodes during their applicable schedule, I have to duplicate each alert with an additional condition in the trigger that checks AlertWindow for each value. Then, I have to add a schedule to each alert based on the AlertWindow value I'm looking for.

This becomes a problem when:

1. We need to change a parameter in an alert that applies to all nodes. For instance, if I want to change the CPU threshold that my tier 1 CPU alerts fire on, I have to make sure I change that threshold on ALL of the T1 CPU alerts, (1 per AlertWindow).
2. If I want to add an additional AlertWindow value, I need to duplicate each of the alerts.