How to check the combined radiation pattern of 3 element array?

Hi all,
I'm designing 3 element antenna array. I have to check the combined radiation pattern of the whole array by varying the inter spacing between array elements. I have acess to VNA, spectrum analyzer and Lab-Volt's LVDam-ant equipment(plot the radiation pattern of antenna). But the problem is that
LVDam-ant equipment plot the radiation pattern of single antenna. How can I get the whole radiation pattern of array?
Is there a way to combine out all the three signals received by the individual antenna elements of array and give me one output that can be feed into the test equipment?
Thanks

Is there any one listening to me??