Hello, 

I am having a custom module "Subscriptions". Each subscription has different invoices (module "Invoices") linked to a subscription. And each invoice has a single line field "Subscription_Issues".

I want to combine all of these values from all invoices and output the new value in field "Combined_Subscriptions_Issues" in the subscription. 

I.e. 

These invoices are linked to the same subscription and they do have a value in the field "Subscription_Issues": 

Invoice 001: A

Invoice 002: B

Invoice 003: C

And I want to combine them and output the new value in the subscription (the invoices are linked to). So the result in the custom module "Subscription" in the field "Combined_Subscription_Issues" would be: 

A B C

How is this possible? 

Thanks for help, 

Michael