Group1 ->Group1_Sub1 and Group1_Sub2

Group2 ->Group2_Sub1

Group3 ->Group3_Sub1,Group3_Sub2

for %%s in (

Group1,Group2,Group3

    ) do (

        echo set Main Group %%s >> Log.txt

        for %%i in (
                    Group1_Sub1,Group1_Sub2,Group2_Sub1,Group3_Sub1,Group3_Sub2
                    ) do (
                        echo Main Group is %%s and its sub group is %%i >>Log.txt
                         )
            )

set Main Group Group1
Main Grpup is Group1 and its sub group is Group1_Sub1
Main Grpup is Group1 and its sub group is Group1_Sub2
Main Grpup is Group1 and its sub group is Group2_Sub1
Main Grpup is Group1 and its sub group is Group3_Sub1
Main Grpup is Group1 and its sub group is Group3_Sub2
set Main Group Group2
Main Grpup is Group2 and its sub group is Group1_Sub1
Main Grpup is Group2 and its sub group is Group1_Sub2
Main Grpup is Group2 and its sub group is Group2_Sub1
Main Grpup is Group2 and its sub group is Group3_Sub1
Main Grpup is Group2 and its sub group is Group3_Sub2
set Main Group Group3
Main Grpup is Group3 and its sub group is Group1_Sub1
Main Grpup is Group3 and its sub group is Group1_Sub2
Main Grpup is Group3 and its sub group is Group2_Sub1
Main Grpup is Group3 and its sub group is Group3_Sub1
Main Grpup is Group3 and its sub group is Group3_Sub2

set Main Group Group1
Main Grpup is Group1 and its sub group is Group1_Sub1
Main Grpup is Group1 and its sub group is Group1_Sub2
set Main Group Group2
Main Grpup is Group2 and its sub group is Group2_Sub1
set Main Group Group3
Main Grpup is Group3 and its sub group is Group3_Sub1
Main Grpup is Group3 and its sub group is Group3_Sub2