How can i hook up my dash speakers with my current amp?

I have a ppi 5 channel black ice amp that is
 90 watts x 4 channels 4ohms
130 x 4 at 2ohms
270 x 2 channels bridged at 4ohms
 sub channel 560 x 1 at 2ohm. 

Front channels have rockford fosgate 100 watt rms components speakers in the doors.

Kicker cs series 100 watt rms coaxil in the back doors on rear channels
And jl audio subs if it matters on the sub channel
I currently have 2 kicker 50 watt rms dash speakers 2 3/4 inch installed but not hooked up. Can these speaker be hooked up to the amp somehow with the rockfords? I know a new amp probably easier but dont want to spend more money on another amp right now. I was curious if its possible to wire them in series and rockfords in paralell to the amp bridged to seperate the power enough for it to work by running the 4ohm kickers to 8ohms in series and rockfords to 2ohms off the same channel. I may be thinking completely wrong on this, but would it work and allow the most power through the rockfords? If not is there any other way to hook up other than straight to factory head unit or should i just sell them? Are the fosgate components hooked up best or should i bridge the channel and hook them up on one channel together. Same questions for the kickers in back doors? Any advice would be appreciated? Thanks
One more question, i have a line converter hooked up for the amp since factory head unit had no rca outputs. I seen the rca plugs for sale on amazon to put the speaker wire directly to the rca plug with set screws. Would the speaker wires to the rca plugs work like that or does it need the line converter for the amp to correctly hook up to factory units without preamps?