How to define the load balancer for back-end servers in apigee microgateway

We are new for the usage of apigee microgateway. In terms of target server, it seems microgateway only supports one backend server and cannot support the load balancer setup as below:

<TargetEndpointname="default"><HTTPTargetConnection><LoadBalancer><Servername="target1"/><Servername="target2"/></LoadBalancer><Path>/test</Path></HTTPTargetConnection></TargetEndpoint>

Is there any recommendation how to load balance a group of backend servers in microgateway.

Thanks!!!