Unfortunately, there is no possibility to configure the schedule of a task in such a way. Howevr, thank you for the suggestion, we forwarded It to the corresponding department for consideration.
As of now, you can achieve the desired using the below script in a condition of your task. The script returns true only if the current hour does not match any of those specified in the $excludeHours variable.
$excludeHours = @(3, 10, 15) # TODO: modify me
# Get current date
$currentDate = [System.DateTime]::UtcNow
foreach ($excludeHour in $excludeHours)
if ($excludeHour -eq $currentDate.Hour)
$Context.ConditionIsMet = $False
$Context.ConditionIsMet = $True