Update parent module based on child modules

Update parent module based on child modules

Hey,

I'm sure there should be a way to do this, but I am struggling to find a solution.

We have a parent module called Sites, and a child module called Plots. We are looking for a solution that would achieve the following:

When all Plots belonging to a single Site are updated to Status: Sold, Site status also updates to Sold.

Status is a drop down on both parent and child module. 

If there were just 1 plot per site, that would be easy, but as there are multiple, I can't work out how to check all child records meet the criteria before the update triggers.

Thanks