The answer is yes.
But you need to know the unique identifer code for QuickBooks firstly.
To be more specific, every name (customer, vendor, item, account name) is stored in QuickBooks with a ListId.
There are two ways to find the Quickbook ListID
The first is found on page 16 of our Legrand CRM Application Note.
The second option is you can access this, if you use QuickBooks SDK tools, QBXML etc - tools that are provided by Intuit to access data in QuickBooks.
More on this can be found on Quickbook user forums such as
Once this is known, by accessing the Accounting action menu you can select Link to Existing Accounting Entity.
This will allow you to enter in that QuickBooks unique identifier code, thus linking the Legrand CRM Company to a Customer already existing in QuickBooks.