As long as each xlsx is set up the same way, just iterate over a list of the files:
FPlist = {"$DESKTOP/temp.xlsx", "$DESKTOP/temp1.xlsx"};
For Each( {val}, FPlist,
Open(
val,
Worksheets( {"Sheet1", "Sheet3"} ),
Use for all sheets( 1 ),
Concatenate Worksheets( 0 ),
Create Concatenation Column( 0 ),
Worksheet Settings(
1,
Has Column Headers( 1 ),
Number of Rows in Headers( 1 ),
Headers Start on Row( 1 ),
Data Starts on Row( 2 ),
Data Starts on Column( 1 ),
Data Ends on Row( 0 ),
Data Ends on Column( 0 ),
Replicated Spanned Rows( 1 ),
Suppress Hidden Rows( 1 ),
Suppress Hidden Columns( 1 ),
Treat as Hierarchy( 0 ),
Multiple Series Stack( 0 ),
Import Cell Colors( 0 ),
Column Separator String( "-" )
)
)
);