This can be achieved (Assuming if you're having both machines on same domain) by using Jump Server. I'll try to explain every scenario where you can implement it.
1. Allows Account1 to be connected to my VM using RDP
You need to assign an IP address to your VM. So for example Account1 wants to access the VM, he or she needs to first login to a server and by defining firewall rule in your jump server you can restrict the user from accessing that specific account to host.
2. Account2 to have access from outside the network and through the local network using RDP as well
Same pattern can be used for account 2 however, you need to create a separate account in your jump server in order to access it.