Alternatively, how about using multi-select control. With this control, on selecting a value(say Abigail starting with ab letters), it is not listed again(equivalent to getting disabled) in the list. Refer the below screen shot:
I think you can create similar functionality by using auto complete and repeating dynamic layout.
1. Create two Page list. One for your source and one for selected items. Add auto complete control with source pagelist.
2.Above autocomplete add one repeating dynamic layout with selected item pagelist, in repeating dynamic layout add a section and in that section use a formatted text/text input with selected items pagelist property name.
3.Now on selection of item from autocomplete. Run a data transform or activity to copy selected item from source pagelist to selected item pagelist and delete item from source pagelist.
4.Same thing you can use to delete item from repeating dynamic layout add back item to source pagelist i.e autocomplete
After reviewing this with our SMEs in GCS, we have decided your best bet would be to get in touch with our Consultint Team to help you with this. Please contact your Account Executive to get that set up.