There are lots of approaches here. The only one that satisfies your 100% criteria is to give up and go home. I.e., none of the approaches are satisfactory. However, your risk here is probably relatively much less than other entrepreneurial risks associated with this venture.
(1) you can conduct a freedom-to-operate search that will perhaps get a relatively good answer for you. One problem is that this won't uncover all patent rights that might have an impact. Another problem is that your actual software implementation will be much more specific that what you stated above. Although the general idea that you stated above might not infringe anyone else's patents, your particular implementation might actually infringe someone else's patents.
(2) Some folks like to obtain patent protection on their own approach with the idea that their own patent serves something like proof that their approach is new (and thus doesn't infringe any one else's patents). While this idea has some logical appeal, I have never seen it accepted by a court of law.
(3) You can obtain business insurance that will cover you in case you are found liable for (non-willful) patent infringement. You insurance may require that you use additional caution.
(4) Your company is unlikely to be sued for patent infringement unless you become a business success or threat. When you are sued for patent infringement, you should take that lawsuit as a badge of honor and respect. While a handful of companies have been put out of business by patent infringement charges, most of the time these cases settle and you go about your business with a little less profit.
Bottom line: Yes, it is fine to spend a bit of time making sure you are avoiding infringing other's patents, but the real focus of a new venture needs to be on how to make an excellent product and how to sell that product.
