I'm using the amazon ebs builder to try and build an AMI in a private subnet. Access to VMs in the subnet must go via a bastion, which in turn must be accessed using AWS session manager. I see that there are ssh connection option in packer for bastion and session manager, but I can't work out how to use them in combination. Unfortunately the source AMI I am using does not support session manager so i somehow need to configure packer to use session manager to connect to the bastion and then establish an ssh connection from the bastion to the build VM. Is this feasible?