Yes you can do it, keep track of each as a separate Class (using Class Tracking-only available in Plus) AND each company is reported under the same tax ID.

No, if each company has a different tax ID OR has different owners – different may or may not include your spouse, […]

Resolution for 'CPB issue: 'can I have two separate companies in one database?' available: Yes.

The CPB issue or error code is a known issue in Quickbooks Online (QBO) and/or Quickbooks. Support for this issue is available either by self-service or paid support options. Experts are available to resolve your Quickbooks issue to ensure minimal downtime and continue running your business. First try to resolve the CPB issue yourself by looking for a resolution described in the article. If it is a complex CPB issue or you are unable to solve the issue, you may contact us by clicking here or by using other CPB support options.

For more information about resolving issues related to CPB in Quickbooks/QBO or to get support for the issue 'can I have two separate companies in one database?', click the link below: