Display only the combination of declared facets attributes for query suggestion spited by comma

Hello,
I am trying to configure based on multiple attributes, using the facets like it is described in documentation. But the query suggestion index contains also suggestion for each attribute, and I need to display only the combination of attributes: e.g “Attribute1, Attribute2, Attribute3” not also “Attribute1”. How can I obtain that? I tried to add as propertied the facets from which a suggestion is composed so I can filter and concatenate the attributes with “,” but I could not find how to.
Can you please advise because I am out of resources to investigate.
Thank you,
Monica