Modify administration group with virtualmin API

I am running Virtualmin Pro and I am in the process of writing a script to add a number of domains and perform some other set-up functions. I found that if I specify a value for the --user parameter of the create-domain command the administration user will be set to that value, however the administration group is set to a value taken from the domain name. I would like to have the administration user and group set to the same value, but I cannot see a means to achieve this, save changing the value manually after creating the domains with the script. What I also noticed is that if I made a change, say to the mailbox suffix found in “Change Domain Name” under “Server Configuration”, the administration group would be also modified to match the administration user. Does anyone know of a way to set the administration group, or force the modification to the administration group, via the API, or am I bound to do it manually?