What you need may not just be infrastructure, but an unattended execution environment. If it's custom, it may need custom development and maintenance. Myself, I use after market-hours to maintain SL-triggers, so have no requirements for live operation. It's a very easy stepping-stone for automation, and leaves intraday for the junkies. For live, you'd need to investigate different options. It can't be easy though, because there's many things that can go wrong, from interpreting analysis-data to managing trade orders. I don't think there's any quick fix other than either do it yourself and weed out the inevitable bugs, or get someone to do it for you, either a partner or an employee. I know there are automation solution offered by some brokers / companies, but they're all very proprietary and specific, so might not be applicable to your requirements. It maybe worth checking out though. This is assuming you can't trust or monitor Ninjatrader. Might be options for that as well in there. Alerts etc., but it will be limited too and not so unattended as you'd like. If you're OK with it, maybe lease a server somewhere to run NT remotely?
Tick data.. Is that data really coming in the right order, or can it be messed up somehow? Have you checked how you will get fills in that particular environment and what the cost of spread might be? Do you have a sound logic behind reasoning of why the trade should work, or is it a find that just show up in statistics? Have you tried the scenario yourself, or would you need to depend on automation to handle it for you?
In short, part of your edge will be in the robustness of the unattended automation, which will require significant time to develop and refine. What might look good on paper, might have different issues in real operations that you would normally avoid manually.