How to schedule a Production to run only during office hours?

Hello,

It is possible, but not on the graphical level or management portal.
You would have to write ObjectScript routines and schedule them via task schedulers. 

The start task script should have something like:

Class YourAplication.ManualProductionStart Extends %SYS.Task.Definition
{

Parameter TaskName = "ManualProductionStart";

Method OnTask() As %Status
{
    Set tSC = Quit ##class(Ens.Director).StartProduction("InsertNameOfYouPrduction")
    If ( $System.Status.IsError( tSC ) ) {
    {
        Do ##class(%SYS.System).WriteToConsoleLog( "Error in ManualProductionStart: " _ ##class(%SYSTEM.Status).GetErrorText( tSC ) )
    }
    Quit ##class(%SYSTEM.Status).OK()
}

}

In [System > Task Manager > New Task] create a scheduled task named, for example, ManualProductionStart.
It should be daily, for example: 08:00

The stop script file should have something like:

Class YourAplication.ManualProductionStop Extends %SYS.Task.Definition
{

Parameter TaskName = "ManualProductionStop";

Method OnTask() As %Status
{
    Set pTimeout = 60 /// means 60 seconds to stop all transacitons
    Set pForce = 0 /// If you set to 1 it will performance a force stop, not ideal, could brak integraty.
    Set tSC = Quit ##class(Ens.Director).StopProduction(.pTimeout,.pForce)
    If ( $System.Status.IsError( tSC ) ) {
    {
        Do ##class(%SYS.System).WriteToConsoleLog( "Error in ManualProductionStop: " _ ##class(%SYSTEM.Status).GetErrorText( tSC ) )
    }
    Quit ##class(%SYSTEM.Status).OK()
}

}

In [System > Task Manager > New Task] create a scheduled task named, for example, ManualProductionStop.
It should be daily, for example: 18:00

But.

A major question. Why the need to start/stop production? 
Fail me to see a plausible reason to do so. Integration plataform should be a 24/7 application.
It more common some business services / operations had a delimited scheduled hour, not all the production.