Our recommendation engine will include any product available in the feed.
Integration modules or your custom product feed differentiate main products to those that are simple variations. If you only want to display main products you can do it for each recommendation block separately or you can do it at account level.
“Main” is a product attribute that has only 2 values: 0 or 1. In order to display only those with main 1, you just enter a valid JSON object, as below. Add this in the include section of Products&Categories