First thing is there is no need to create 7 replication partners.
Second thing more than 5 replication partners with Embedded database will give you problems later on hence avoide it.
You can set up GUPs fro your Site A to G
Create Groups A , Group B ...........to Group G.
Create one Group update provider for each group.
Now As Cycle tech told Create % Admin account your main SEPM & give them limited privilages & let Admin for Group A see only Group A clients. hence this way you can get what you are expecting with very simple setup.
There is no need to seyup replication in this case.
Hope this helps you.