Hello Jacob,
Thanks for reaching out to the Skuid community.
You absolutely can create child records using a custom mass action snippet!
An example of creating lookup references can be seen on this question from a couple days ago, but the logic would be very similar (if not the same) for a Master-Detail records:
Create records in a table based on selected records in another table
If you need any help adapting that example for your use, please feel free to reply to this thread and we’ll see what we can do for you.
