Prestashop - Merge multiple CSV/Excel files into one file - Complex Merging & Duplicated rows

We want to launch an e-commerce using Prestashop. We have 7 Suppliers and each of them provide us with a CSV file containing all their products. The problem is each CSV file has a different layout and by this I mean different "fields" or "attributes". The task consist in merging all of the different CSV files into one. The Freelancer should analyze each CSV file provided by the suppliers, look for common fields or equivalent fields, and having all these in account then merge all files in one. This file should be ready to be used right out of the box. That is why, we will priorize people with some knowledge in e-commerce platforms (Prestashop is a plus). The freelancer should also make a CSV containing all of the products categories. For this he should analyze the products and extract the major categories. We will provide the Freelancer with all the CSV files from suppliers and an example 2 CSV files (Products + Categories) proposed by Prestashop. Freelancer should have insight in order to decide which fields should be included and which one do not. We are not interested in our suppliers internal system attributes (product id, etc) but in the products one such as name, description, available sizes, available colors, images, etc. The Freelancer should also standardize the different sizes. Example: extra-small, xsmall should be changed into XS or extra-large, large should be changed into L. In addition to this, some suppliers have many rows for one product. So all this rows should be merge into one row and they must keep all unique values. For example: name | size | color Nike super shirt | small | blue Nike super shirt | large | red -> should turn into -> name | size | color Nike super shirt | small, large | blue, red Fields should be separated with “;” and multiple values with “,” Here is a list of the different suppliers: -SanMar -Alpha -Hit -Leeds -Bic -Bullet -Nordwood The person who decides to take the job should read this page: http://doc.prestashop.com/display/PS16/CSV+Import+Parameters There are several youtube videos as well that could help. This is a difficult task that requires analytical power and fluency with big amounts of data. The mandatory fields are: name, price, supplier, description, sizes, images, colors, category . This fields should be completed for all products. This is very important.