Update InfoPath field in a Repeating Table with Nintex Workflow

How to update a column in a InfoPath repeating table based on the selected user in a other column?
I wanted to add several users to a repeating table and after submitting the form the computer, location etc. from the selected users needs to be added via a workflow in the form.

The structure of the form is as follows: we need the field AccountId that is a child from Person, which is a child from gpContactSelector, that is a child is from group4, which is a child from group 3 and finaly the parent is myFields.
The XPath for this field is:

/my:myFields/my:group3/my:group4/my:gpContactSelector/my:Person/my:AccountId

The workflow has the following actions:

Add a Query XML on the Current item and add the XPath path, store the results in a collection variable

Add an for each action that process the collection and a text variable.

An Update XML
XML source is current item

Create the following Xpath query:

• /my:myFields/my:group3/my:group4/my:gpContactSelector/my:Person/my:AccountId.  Go to the parent of the field AccountId 
• [my:AccountId={Workflowvariable:Created Text variable}]
• /parent::my:gpContactSelector/parent::my:group4/my:FromLocation. This tells the query to go up two levels to come to group 4 and select there FromLocation

Select Update node value
Add the variable you want to set in the FromLocation

Just a last few point:

• This workflow doens’t do anything more than retrieving and updating, other options you have to add yourself
• For more XPath see http://www.w3schools.com/xpath/default.asp
• To get the Query I used Altova XMLSpy