Fare Question

Hi Guys,
Hopefully a quick one that someone can answer
We are a family of 7 travelling to MCO on the 21st of October for 2 weeks, returning on the 4th of November.
I am currently trying to book our tickets but having some pricing issues when trying to do so.
I am guessing its to do with only a certain amount of fare codes being available per booking, as i am trying to book this in two bookings. One with 2 adults and 1 child and one with 3 adults and 1 child. The 2 adults 1 child fare price is fine, but as soon as i do the 3 adults 1 child, the price pretty much doubles. If i change it to 2 adults 1 child again, fare goes back to normal. The only thing i can think to do, is book 2 adults and 1 child twice and then 1 adult on their own with a separate booking. What i am worried about is doing this and getting to the last booking and the price doubling. Is it a case of getting through to the booking stage on all 3 bookings and hoping it keeps the pricing??
Sorry if this is a stupid question.
Thank you
Ben
Hopefully a quick one that someone can answer

We are a family of 7 travelling to MCO on the 21st of October for 2 weeks, returning on the 4th of November.
I am currently trying to book our tickets but having some pricing issues when trying to do so.
I am guessing its to do with only a certain amount of fare codes being available per booking, as i am trying to book this in two bookings. One with 2 adults and 1 child and one with 3 adults and 1 child. The 2 adults 1 child fare price is fine, but as soon as i do the 3 adults 1 child, the price pretty much doubles. If i change it to 2 adults 1 child again, fare goes back to normal. The only thing i can think to do, is book 2 adults and 1 child twice and then 1 adult on their own with a separate booking. What i am worried about is doing this and getting to the last booking and the price doubling. Is it a case of getting through to the booking stage on all 3 bookings and hoping it keeps the pricing??
Sorry if this is a stupid question.
Thank you
Ben