patent violation exposure when adding an incremental and novel missing piece

I will explain my question as an example...If I want to build and sell
a novel analytic technique capability and also the corresponding
financial software system, but there are 100's of patents on financial
software systems, what is my legal exposure ?  Do I need to pay
royalties to everyone along the way who has patents regarding basic
financial system techniques, or do I just need to patent my analytic
technique, build a financial software system, and not worry so much
about the other patents ??

I guess what I am saying is, I want to produce something novel that is
the last incremental missing step that sits on top of (most likely) a
series of existing inventions, and I need to build and market those
existing inventions (financial system) to enable the marketplace to
use my novel approach (in this case an analytic technique)..just
integrating with an existing system is not good enough, b/c I need to
control and optimize the code to use the technique..

Any tips would be appreciated with this dilemna !

Claus