"it only allows one field to have relationship between both tables."
Actually you can do this, though creating an additional table to join employee records to location records instead of a series of location fields would be much easier for you to work with.
First to explain how to link a second field to an already related table so that you have two relationships instead of one relationship with two pairs of fields:
You probably have the following in your relationship graph:
Employee::Location 1 = Locations::Location Name
Click on the Locations box (this box is called a table occurrence) to select it.
Click the button with two green plus signs to make a copy of this table occurrence. Filemaker will name this Locations 2, but you can change this name if you want.
Drag from Employee::Location 2 to Locations 2::Location Name
You now have two relationships linking the data source tables Employee and Locations using two different table occurrences, Locations and Locations 2.
A better approach to make your database easier to work with:
Define a new table, Employee_Locations, with two fields:
Link it in between the Employee and Locations table:
Employee::EmployeeID = Employee_Locations::EmployeeID
Locations::Location Name = Employee_Locations::Location
Now you can base portals and reports on the Employee_Locations table and you no longer need multiple location fields in your employee table.
You can place a portal to Employee_Locations on your employee layout and add fields from the Locations table to show address etc once a location has been selected.
You can then build your report on a layout based on Employee_Locations and add fields from both Employee and Locations to provide the info you need.
Note: you might also use a Location ID number instead of a name in these relationships. Locations can change names and if that happens, changing the name in your Locations table will break these connections.
Many folks get confused over the terms Table and Table Occurrence. To learn more, click the following link:
Table vs. Table Occurrence (Tutorial)