One way to achieve this is that you can configure the following actions on the primary checkbox where you make the selection. post value > set value and set the value of the second checkbox which you want auto updated to the property of the current checkbox and refresh section on the check box which you select/deselect. (see image below)
That should fulfill your requirement.
I tested the same at my end and I was able to create the scenario as desired by you.
I created two checkboxes with properties check1 and check2 of type truefalse. Configured the actions as the image below.
Try this once, For Example you have property Name (sample - DataType(boolean)) for Select All If the Sample==true then run the transform to loop through the pagelist and set the property (pySelected) of the other checkboxes to true and do a refresh list.