Nested loop in groovy to run the test case

Hello All, 

I am having difficulty in using nested loops in groovy for running the below scenario:

API call : http://[host]/variable1/varaible2

Test Data: Variable 1-

V1 

V2

V3

Variable 2- 

E1

E2

E3

E4

I need to call the API for all values in Variable 1 with all values in Variable 2. 

how can i do this in groovy script because this API call is another test case and I need to run the test case using groovy script testrunner method.

Please help!!