Can the HRV/ERV unit be tied into a central HVAC ducting system?

No, it will cause an extreme imbalance between the fresh and extract air. The unit will not be able to function as designed and will greatly decrease transfer efficiency. Novus units are an exception, but still not recommended. It will only provide adequate ventilation to all rooms when the large central HVAC fan is running which is generally only a portion of the year.