How to create a standard file template to load the data in BW

Hi Experts,

I have a requirement in which different users are going to sent their financial statement in file format. We are having around 10 users from different geography.

The challenge is they are not using the standard format to fill the details. Hence could you please suggest how we could achieve this in BW and how can we load all these 10 files with one standard template, one option is via macros in excelsheet but not sure if tomorrow some changes happened to Excel we will have challenge.

We are using sap BI 7.3 version.

Hence could you please suggest the best strategy to approach.

Thank You,

Reena