Develop search engine to search in data files

Hello everyone I am looking someone to complete this task: Need to make data search on website (search inside big data files) How it will work: 1. We upload in backend for example 10 databases in excel or csv files and these files inside has thousands or sometime millions of rows and around 10 different collumns. So we need to make search on website according several criteria, for example Country, Category, one more category (will be around 4 criteria to select) and then user should see how much contacts in inside with these criteria. 2. I should be able to download these rows after search in backend or to send them to specific email address. 3. This program with all databases should be on separate server from the website and should be made in secure way (I dont want anyone from website server to be able to download this information).