You can do this using BatchConvert. Here is a sample script :
Dim cdi
Set cdi = CreateObject( "cdintf.cdintf" )
cdi.DriverInit( "Amyuni PDF Converter")
cdi.SetDefaultPrinter
cdi.FileNameOptions = 7
cdi.DefaultFileName = "c:\wutemp\emf.pdf"
cdi.BatchConvert "c:\temp\*.emf"
cdi.DriverEnd
set cdi = Nothing
Note: you need to add EnablePrinter and use CdintfEx to make this code work with version 2.1