Google Compute Engine supports specifying the service account to use for the instance.
You can create a new service account, assigning the Project Owner or Editor role ( as you want) and then assign that service account to the instance you want.
You can also assign instance-specific roles and permissions form the Cloud Engine - VM Instances Page as stated in the Compute Engine Official Documentation:
- Go to the Computer Engine VM Instances page
- Click the checkbox beside the instance(s) to which you want to assign instance-specific roles.
- Click on "Show Info Panel".
- On the "Info Panel" on the right side of the screen under "Permissions" click "Add Members".
- Select the members / roles you want to assign and click "Save".
Please have a look into the following article explaining Compute Engine Service Accounts.