Can you use a single webhook to create multiple records in a child table

You could create a formula text button that could use the api_editrecord to check the box on that record and also use the api_addrecord to add a record with the information you need to the other table. You could even go a bit further and make the button uncheck the box and delete the record. It is a bit complicated at first but easier to master than you think. If you can webhook you can learn this.
 If this is an avenue you want to pursue send me an email. I will give you examples and be able to answer questions.