You will really need to use code to do this.
Try this:
Create a text file that looks like this
Path to each file, first slide to add, last slide to add each on a new line
"C:\Users\John\Desktop\Pres 1.pptx",1,1
"C:\Users\John\Desktop\Pres 2.pptx",2,3
etc
Then run this code (get back if you don't know how)
Code:
Sub PasteSlides()
Dim filenum As Integer
Dim strBuffer As String
Dim rayData() As String
filenum = FreeFile
' change to your text file location
Open "C:\Users\John\Desktop\data.txt" For Input As filenum
While Not EOF(filenum)
Line Input #filenum, strBuffer
rayData = Split(strBuffer, ",")
With ActivePresentation.Slides
.InsertFromFile rayData(0), .Count, CLng(rayData(1)), CLng(rayData(2))
End With
Wend
End Sub
Make sure you check it out with a not too important file first!