how to duplicate this mainframe process on iSeries?

List,

Here's another unusual process we have on our VSE mainframe that will have 
to be duplicated on the iSeries. I am hopeful that the iSeries can handle 
this in a much easier manner than does VSE, but I am too new to the 
environment to know.

Here's the process on VSE....

During the day, depending on which customers' data has arrived, it is 
processed and their data "staged" to a sequential file in a specific VSAM 
catalog. Throughout the day, more data files are generated. When it is time 
to begin the nightly run, we have to "gather" these files together (merge to 
a single dataset) and then purge the original individual files. (the catalog 
is backed up before the process begins)

The way this process is currently handled is a COBOL program reads the VSAM 
catalog, looking for datasets whose name matches specific templates. This 
program generates JCL for a second job where another COBOL program will 
process each of the specific files passed in the list that the first program 
prepares. There is only one input file defined in this program. Before each 
input file open, an assembler routine is called which overrides the "ASSIGN 
TO name" of the file hardcoded in the ASSIGN clause of the program with one 
that is passed to the program in the list. This way it opens and processes 
each file dynamically according to the list for that day.

If the iSeries provides a way to concatenate files of a similar format with 
names that match certain template(s) to a single file, this will be a piece 
of cake. The constraints here are:

1) there will be one-to-many of these files for any given run - but all in 
the same library
2) the files will be identified by one of several "strings" in their 
physical names
3) it is possible there could be other files in the same library but are 
irrelevant to this process (so #2 is very important)

How best to accomplish this on the iSeries?