@Justin Young
I agree with @Brent Coombs - this strategy isn't bad, but it will be very slow. You're likely to get only a few hundred dollars per month of cash flow from your properties and putting that toward their mortgages will not really pay down the principle that fast, especially considering that you pay more interest than principle at the beginning.
You're also buying turnkeys - so you will purchase them at market prices. This will give you minimum equity, so you don't have any wiggle room if the prices in your markets fall. You will then be unable to sell them or will have to take a loss, which is counter productive.
When you're first starting out with real estate, in my experience, your biggest growth potential comes from the money you can save from your regular job, not from your properties. After 5-10 years, your cash flow will be much higher, the properties will likely go up in value and your mortgage pay-off will be noticeable. But until then, provided that you have a relatively high paying job, that will be the biggest source of your growth.
I don't think there is anything wrong with purchasing turnkeys, but I don't think you should count on them to finance your multifamily property and I would not use their cash flow to pay down their mortgages. Why not just save all of the cash flow, add your personal savings to it and use this to save enough for a downpayment on a multifamily property?