Can you recommend three car seats to fit across the back of a Hyundai Santa fei?

[Pitapotamus]

I can't seem to find a combination of seats that will fit across the back seat of my car. We need two high back boosters for a 3 (nearly 4) year old and a 5 year old and a rear facing seat for a baby. At the moment we have the cybex Sirona that we'll use for the baby and a cybex high back booster or a kiddy guardian fix high back booster that we can use for one of the older children but we can't fit all three in a row. If anyone has a combination that will work that advice would be greatly appreciated!