InfoPath Dev

Hi I have a repeating section with checkboxs

Checkbox 1 Name 1
Checkbox 2 Name 2
Checkbox 3 Name 3

I have another hidden text field (Allnames) that will collect all the names checked.

I have created action rule as follows
When checkbox = TRUE
Set field's value: Allnames = concat(Allnames, Name, ", ")

So when my user check checbbox 1 and 3 for example, the field Allnames looks like this Name 1, Name 3,

I need to create another rule to delete the Name when the checkbox = FALSE
I don't know how to do this part. Can someone please assist?
Thanks Johnny

Maybe use a default value for your "all names" that uses a double eval and an XPath filter. I'm attaching a simple sample. Right click the link and save the file locally, then right click the file and select "design" to open in design mode.