Subitem automation when update is posted

I would love to see an automation option for subitems to use an update that is posted in a subitem to set a date field forward by x number of days to initiate a reminder to update a subitem. This works wonderfully for us in a item automation for 1 and 2 week reminders and having this for a subitem would be especially helpful in creating efficient automations. No third party offer these types of automations either!