Siblings collection
Metafield editor
Feature introduced in Broadcast 3.5
The second required metafield is theme.siblings
theme.siblingsThe content type is: Single line text and One value.
This metafield maps each product to the correct collection handle for the siblings.
Start by defining a Products metafield and name it Siblings. Then change the Namespace from custom to theme and the key to simply siblings.

Next, add a description. You can name this one Collection handle for siblings. Then click on Select content type and choose Single line text and One value:

Save the definition.
Check the saved metafield
Your second metafield should look like this:

Please ensure you change the Namespace and key to this custom version for Pipeline:
theme.siblings
By default, the namespace begins with custom. This will need to be changed to theme
Product setup
Next, we will use these newly defined metafields in the Product Setup for each product:
Siblings product setup