S-DOC : Creating Batch Documents from a Flow

I have a flow that grabs records for an object and displays them in a Flow Data Table. My current flow, loops through the ids of those records and creates separate s-docs for each record id.  I know this isn't optimal, and I was wondering if anyone has created a flow to create a batch document using S-DOC in a Flow. 

I see in their documentation that they have an apex class, visualforcepage, and button to accomplish this from the list view of the object. But, I want to do a similar thing but based on the records selected in the flow. 

Question: Can I call the apex class in the flow? Or do I need to convert it something in order to do that. 

Any thoughts are appreciated. 

this is the documentation for the sdoc with the apex class info: https://www.sdocs.com/knowledge-base/sdocs/batch-processing/the-s-docs-mass-merge-feature/#step-5-use-the-mass-merge-amp-batch-document-feature