Looking for advice in how to build this project

Hi all,

I need some ideas for designing a solution for the following project.
There are 10 applications developed in Ms Access, Ms SQL, and Oracle.
All of them are stand-alone applications that use their own tables and
do not share anything with any other application. Some of the tables
used in these applications are very similar, and some of the information
is duplicated.

The project goal is to integrate these 10 databases/applications. To
make them share data, in a way that a user could get a summary report
with data from 3 applications, etc.

How will you do that?