Use two variables to maintain the "Back" and "Forward" selections.
The "Back" selections will be kept using a Concat() function and set analysis e.g.
and the "Forward" selections:
You can then create two button/text boxes with an Action to make the respective selections in the field ABC.
Thank you for the idea.
I need to play with it a bit (for example how to adjust this concatenated string to be used in actual Selections process), but I like the approach.
The "Select in Field" allows selecting one value at a time, correct? Not sure how to work around this limitation.
Any reason you've added parenthesis to this strings above? I do not think they need to be there, especially if you need to use this string during "Select in Field" calls