Using Contact Triggers to update embedded data in a loop and merge block

My use case is this: Each customer (respondent) has an inventory of products that are stored as embedded data. The products have attributes that are also stored in inventory for each product. e.g. Prod 1 has Name1, Description1, usages1, weight1... and Prod2 has Name2, Description2, usages2, weight2....up to 20 products. The customer can review the each of the products and it's attributes, and modify if needed. The updates made on the review will update the embedded data fields for that product.

To do this, I set up a multi-select question (Q1) that asks the respondent which products they want to use. I have pre-populated this from the Name1 for each product in their ED. Then I have a loop and merge block set up with each of the products w/attributes as L&M fields. The L&M block contains Form questions (Q2), dropdown select questions (Q3), etc. which will display the attributes of each product by setting the default value to the L&M fields based on the loop. The L&M block loops based on the selected choices in Q1.

I was able to use contact triggers to update embedded data based on a question response outside a L&M block. Is there a way to do it inside a L&M block - after every loop?