If I understand correctly what you want, you can do this with Default Values.
Open the Data Source task pane, and go to those 3 fields you want populated, but don't want to show in the repeating table. Give them a default value by pointing them to the fields at the top of the screen. Make sure the check box is selected which will update them if the value changes.
This way the fields will auto-populate with the values of the fields at the top of the screen and you don't need to show them in the repeating table.
Hope this helps.

Signature
Greg Collins [InfoPath MVP]
Visit http://www.InfoPathDev.com
Hello,
I have an unusual problem. I need to disable the repeating
functionality of a repeating section. I was given an xml schema that I
have to work from and cannot break. It looks something like this:
Projects (group)
---Project (repeating group)
---field1
---field2
---field3
---field4 (client number)
---Tasks (group)
------Task (repeating group)
------field4
------field5
------field6
I have an area at the top of the form to input values for field1-3,
then have a separate area for the repeating projects' task's fields (a
repeating task table in a repeating project section). They both are
automatically repeating sections because they were predefined that way
in the XML schema. So there are multiple projects with multiple tasks
inside. The problem is that all project information is the same
(field1-3) for each repeating project, I don't want it to repeat
onscreen (but it should repeat in the data structure using the same
values that the user inputted). I don't know if this complicates
things, but I do have one field (client number) that changes with each
project, it is embedded in the project repeating section which also
contains the task repeating table. It's a strange request and what
I'm being asked from the business side isn't matching what I have to
work with from the IT architecture side. Thanks in advance.
Anthony