Recently on the TechNet forums, someone was attempting to disable a response group queue time-out and overflow programatically within a PowerShell script. In the control panel, there is an obvious check box, but in the PowerShell object, there is no obvious Boolean equivalent to enable/disable.
The simple trick is to set the TimeoutThreshold and OverflowThreshold values to $null instead of a numeric seconds value.
The following simple method will clear both of these checkboxes for you.
$My_RSG_Queue = Get-CSRGSQueue -identity [Your-Queue-Identity]
$My_RSG_Queue.TimeoutThreshold = $null
$My_RSG_Queue.OverflowTheshold = $null