Hiding and then making select-options visible on the selection-screen

I've created a selection screen. On this i've got a field (pr_inpt) depending on whose value i have to display the rest select-options viz. (so_c1, so_n1, so_d1, so_t1) say ,

1.)if (pr_inpt) contains value 'A' then display (so_c1 & so_d1)

2.)if (pr_inpt) contains value 'B' then display (so_n1, so_d1 & so_t1)

To achieve it, in the initialization event, i looped at the screen and for all (so_c1, so_n1, so_d1, so_t1) i made screen-active = '0'. Due to this my objective to hide fields in the beginning is achieved.

Next when user is entering value into (pr_inpt), i am making screen-active = '1' at selection-screen output event, for those relevant select-options (say if A, then made active for so_c1 & so_d1) but my problem is that it is making all select-options (so_c1, so_n1, so_d1, so_t1) visible on the screen which i don't want.

How can i achieve this, also is it possible to change the label of the select-options while displaying.

Plz help.