This feature is only compatible with GroupDocs.Assembly for .NET 3.1.0 or later releases.
Explicit Support for Multiple Data Sources
Using DocumentAssembler.AssembleDocument overload user can reference multiple data source objects and their members in the template. Names of all the data sources must be specified and unique.
Parameters
DataSources
An array of data source objects like object[] dataSources.
DataSourceNames
An array of names to reference the data source objects within the template like string[] dataSourceNames.