Add functionality to read XML body from files in File - XML datasource

We have multiple collections of XML files that are all of the same XML schema. These files are accesed through the File - XML datasource.

Currently, processing XML files from this source requires that a transformation is defined on each file. That means we need to add a new transformation for every file that gets added to a collection, which occurs several times a day. That is not very convenient, as it is hard to automate, especially when these transformations need to be modified.

For similar cases, where we have the XML in a relational data-source (as a field of type XML and a schema definition in TDV), we apply a passthrough procedure where we pass in the XML contents and connect a transformation to the output of that (single) procedure. Thus, we can define a single transformation, can loop through the XML results and feed each to the transformation. That's a process that is largely automated.

For example, we use a passthrough procedure like this, with the XML Schema definition used as the type for the INOUT parameter:

PROCEDURE passthrough_ContractCancellationResponse(
INOUT ContractCancellationResponseXML /shared/SME/"5_Sources"/Globals/DefinitionSets/Sharepoint/ContractCancellationResponse_1p1."{urn:nedu:edsn:data:contractcancellationresponse:1:standard}ContractCancellationResponseEnvelope"
)
BEGIN
END

We would like to similarly be able to loop through the files in the File - XML datasource (possible), get the XML body of each file (currently not possible) and, for example, pass it through to a procedure like the above to transform the data and obtain the results.