Need help for our thesis.

Gud day! We are currently having our thesis for our undergarduate course and this involoves the code of PostgreSQL. Basically, our thesis needs a modification of the existing code of the said database. As of now, our University has an existing online registration system which uses Postgre as their back end. But the problem is the existing one is not a distributed system. Our thesis adviser would like us to deal with the load balancing of the said online registration. He wanted a multidatabase querying. For example, we knew that the following statements are posible,

                   select *

                   from t1, t2., t3;

provided that t1 and t2, t3 are tables from a single database.

Our thesis is to make the following satatement legal

                  select *

                  from d1, d2, d3;

provided that d1 and d2, d3 are separate databases.

We are currently having our research about this problem and as beginners, we surely need help from experts like you. Any form of comments and suggestions will surely be appreciated by the group.

      Thank you very much and hope to here from you.