5 radio buttons enable disable

Hi Experts,

I have selection screen like this.

And i have 5 radio buttons with same group.

rb_gene,

rb_upld,

rb_dcon,

rb_dtmp,

rb_delc

REPORT x.

TABLES: mara.

SELECTION-SCREEN SKIP 1.

SELECTION-SCREEN BEGIN OF BLOCK a1 WITH FRAME TITLE text-001.

PARAMETERS : rb_gene RADIOBUTTON GROUP r1 DEFAULT 'X',
             p_matnr   LIKE mara-matnr ,
             p_charg   LIKE mcha-charg ,
             p_datum   LIKE sy-datum.


SELECTION-SCREEN BEGIN OF LINE .
SELECTION-SCREEN COMMENT 24(13) text-042 FOR FIELD rb_dwl.
PARAMETERS : rb_dwl RADIOBUTTON GROUP r2 DEFAULT 'X'.
SELECTION-SCREEN COMMENT 40(21) text-043      FOR FIELD p_dir.

PARAMETERS : p_dir     TYPE localfile.
SELECTION-SCREEN END OF LINE.

SELECTION-SCREEN BEGIN OF LINE .
SELECTION-SCREEN COMMENT 24(13) text-003
                   FOR FIELD rb_eml.
PARAMETERS : rb_eml RADIOBUTTON GROUP r2.
SELECTION-SCREEN COMMENT 40(21) text-044
                   FOR FIELD p_rec.
PARAMETERS :           p_rec(50) TYPE c.
SELECTION-SCREEN END OF LINE.

SELECTION-SCREEN SKIP 1.

PARAMETERS : rb_upld RADIOBUTTON GROUP r1 ,
             p_file1 LIKE rlgrap-filename,
             p_file2 LIKE rlgrap-filename.

SELECTION-SCREEN SKIP 1.

PARAMETERS : rb_dcon RADIOBUTTON GROUP r1 .
SELECT-OPTIONS s_matnr FOR mara-matnr.

SELECTION-SCREEN SKIP 1.

PARAMETERS : rb_dtmp RADIOBUTTON GROUP r1 .
SELECTION-SCREEN SKIP 1.

PARAMETERS : rb_delc RADIOBUTTON GROUP r1 ,
             p_matnr2   LIKE mara-matnr ,
             p_datum2   LIKE sy-datum.
SELECTION-SCREEN END OF BLOCK a1.

Depends on user authorizations i would like to display radio buttons accordingly.

For example, if the user have permission to access radio button 1 & 3

remaining 2, 4, 5 radio buttons should disable.

How can i do. Pls suggest me the way... pls give me the sample code if possible.

thanks

kaki