How to set values and select one of the values among it dynamically to combo Dropdown?

How to set values dynamically to combo Dropdown?

?COMBO1{PROP:From} = ‘A|B|C’

I need to dynamically select value

SELECT(?COMBO1, 2) will select ‘B’ from my 1st example.

If you want to change values, you can assign different values like Mike’s method;
?COMBO1{PROP:From} = ‘A|#1|B|#2|C|#3’ (A -> 1, B -> 2, C -> 3)
?COMBO1{PROP:From} = ‘A|#5|B|#8|C|#6’ (A -> 5, B -> 8, C -> 6)
or
?COMBO1{PROP:From} = ‘XX|#1|YY|#2|ZZ|#3’ (XX -> 1, YY -> 2, ZZ -> 3)