How to save results from SC repeat to single database field as array

I got this repeat action in server connect API action:

insert_images insert new records to the product_images database table:

Now I want to store the ids of the above added records as an array to a field in the update_product_images db table, so I set that up this way:

This results in the product_images db field (where I want all the product_ids to be stored as in an array) to be updated with the image_id of the last inserted record from the insert_images table.

How can I get all the ids stored in one single field in the product_images db field?

Thanks for any help in advance.