Selection screen

Hi Folks,

Question 1:

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I have a selection screen in such a way,

i have 2 selection blocks.

in 1st selection block i have 2 radio buttons .and

in 2nd selection block i have 2 select-options.

If i select 1st radiobutton in first selection box then

1st select option in second selection box shud be grayed out and vice versa...

How can i achieve this???

Question 2:

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I have a selection screen in such a way, i have 2 selection blocks.

First selection block contains 2 radio buttons of group rg1.

2nd selection block contains 5 radio buttons of group rg2.

If i select 1st radio button then first 2 radiobuttons in 2nd selection block shud be grayed .

How can i acheive this functionality??

Points will be rewarded in full....

Thanks in advance...