Create Multiple SPGroups in all the subsites if the SPGroups doesn't exist

1) I have sub sites x,y,z under my Site

2) I have groups Group A, Group B

3) Members of Group A are Member1, Member2, Member3

4) Members of Group B are Member1, Member2, Member3, Member4, Member5

5) I need to create the groups in the sub sites if they doesn't exist.

Please let me know for any better approach .