@jacksonp The issue I'm having is that the search.lookupFields request I am using requires the internalID of the parent record, in my case this is 6. I want to be able to get this internalID, 6, from one of the custom fields in my child class. So for instance, in my child class I have a field that says this child belongs to "MySalesOrder". MySalesOrder is the value of that dropdown field, but I want the internalID of MySalesOrder, the one that has the id parameter of 6 in the url.

You can target the drop down menu and get the value. I hope I am understanding your question right.