2 outlet box wiring

I made a new circuit with 1 set of two duplex receptacles and they are working fine. That's all that is currently connected to this circuit. To branch off of one of these duplex receptacles to feed another NEW set of two duplex receptacles do I just get a new strand of 12/2 wire and connect the black to brass screw and white to silver screw and ground to ground on the in place duplex and run that strand of 12/2 to the new duplex receptacle that I'm trying to add to the circuit? My problem is the grounds. I have the ground from the 12/2 from breaker connected to first existing duplex and jumping to the 2nd duplex. So both screw already have a ground. How do I place another ground to jump to the two new duplexes I'd like to add? Should I just remove the ground to the existing set and use a wire nut with a separate bare ground from wire nut to each of the existing duplex receptacles and then a 3rd separate strand from that wire nut to the new 12/2 that's jumping to the new duplex that I'm putting in and do the same on the new receptacles? I understand the basics and how to wire but I'm having trouble with the grounds and tying them together without attaching 2 bare grounds to one terminal screw. Thanks

Hello everyone I am doing a little project in my basement. I wanted to install 9 outlets on my wall. I ran all the conduit and pulled the wire. I want the nine outlets to be on six different circuits. I drew this diagram outlets 1,2 will be on the same circut. 4 will be alone on a circuit. 3 and 6 will be together, outlet 5 will be alone and 9 will be alone. Outlet 7,8 will be together. My question is how do I connect 8,7 together