Three car seat Question - For Moms of 3

yourmom5309

We are expecting our third baby.  DD1 is 25 months old and DD2 is 12 months old.  We have a Trail Blazer and a Camry.  We will probably buy a third row vehicle sometime in the next year or two, but plan on using three car seats across the back of our cars.  Have any of y'all done this?  If so, do you have any recommendations on seats that fit?  Right now we have two Britax, one peg perego, and one Greco.  We will need two more car seats since DD1 won't be big enough to move to a booster.