Hello,
this is just an idea not sure if its a secure method or not (it can be extended as long as you know bash) :

on Node :
useradd -d console-user
passwd console-user

create file /home/console-user/enter.sh with below content :
#!/bin/bash
exec sudo /usr/sbin/vzctl enter Container-ID

now add root powers to that user to execute vzctl via sudo
execute visudo

and add
console-user ALL=(ALL) NOPASSWD: /usr/sbin/vzctl

last thing
chmod 755 /home/console-user/enter.sh
usermod -s /home/console-user/enter.sh console-user

now when you login with console-user you will enter to VPS with Container-Id (specified in our enter.sh) as root .

Highest Regards
Mohammed H