Join results of an Aggregate with results from an Action

In my application, I have an entity that performs a mapping.  This application also has an Action that returns a list of values that can match a field in the entity.  I want to be able to join these to result sets together like a SQL join, but have been unable to do so.  In typical C# code, I can join two lists using LINQ.

To visualize my contrived example.  Each below can return many items, but the list returned from Action can have matching Groups.  The output of this "join" would be similar to an inner join.  I only want to return Roles from the Entity that have matching Groups.  I can think of a way to do this with a ForEach, but that seems slow if these lists get large.

  • Group
  • Role
  • Group

You have the ListAppendAll to save the ForEach, but you need to have both lists with the same structure (same entities).

Hope that helps.