You can follow below steps to achive this. Create one global number field as "gTechnicianID" in Service Report table. Now create one relationship based on
ServiceTechnician:gTechnicianID :: ServiceReport:technIDfk
Now create one valuelist to select the techician name from the list based on ServiceTechnician to show all Technicians ID and Name with value shows from Name field only. Show the portal based on ServiceTechnician:gTechnicianID :: ServiceReport:technIDfk relationship just below to the valuelist.
So this relationship will show the list of service report of selected technician.
I hope this will work for you. Anymore help will be appreciated.
I cant get this to work, It shows the same technician name; (which table to make global field i tried both tables ServiceTechnician and ServiceReport but both did not work)