Hi sheryl3,
Intuit supports the conversion of your Xero transactions to QuickBooks Online (QBO) through a CSV file format. You can reach out to the Xero support team if they have a CSV file of your transactions. From there, you can import them to your QuickBooks.
You can check this article on how to import bank transactions using Excel CSV files from your Banking page.
However, for your two companies, QBO only supports one company to one QBO account.
Keep in touch with me if you have further questions. Have a good day!