Joining two tables

I have a MSSQL database that I have reverse engineered and I am unable to change alter the database presently. The database has two tables for guests and both the same primary key (guests are maintained in two places for an odd reason). They are not related to eachother by actual relationships in the database which makes it very difficult to manage, but could be using a join on their keys. How could I go about what essentially amounts to a join between these two tables and show them in one table in list.jspx when I perform a web mvc setup? Any help would be greatly appeciated.