How to run tasks in parallel with different parameters?

[Vasmi Abidi]

Hi,
   How can I run commands in parallel on multiple remote targets, but with
different parameters?
fabric version 2.6.0

Specifically, I want to run the following in parallel:
      on host1: "iperf3 -c 192.168.20.2"
      on host2: "iperf3 -c 192.168.20.3"

 With fabric1, I could do the above with env.host_data[env.host]
 How can I do it with fabric2?

result = ThreadingGroup(host1, host2, user=username,
connect_kwargs=kw).run("iperf3 -c <dst_ip>")

Is there a way to pass in different values of <dst_ip> to host1 and host2?

thanks,
Vasmi