supress lines in chart

[reddyogili]

hi i have a 5 formulaes in my show values dialogue box in the line chart.{@Impact1}....{@Impact5} of my report based on parameters.

//{@Impact1}:
if {?Impact1} = 1.0 then {NETCOOL_HISTORY.IMPACT1} else
if {?Impact1} = 2.0 then {NETCOOL_HISTORY.IMPACT2} else
if {?Impact1} = 3.0 then {NETCOOL_HISTORY.IMPACT3} else
if {?Impact1} = 4.0 then {NETCOOL_HISTORY.IMPACT4} else
if {?Impact1} = 5.0 then {NETCOOL_HISTORY.IMPACT5}

//{@Impact2}:
if {?Impact2} = 1.0 then {NETCOOL_HISTORY.IMPACT1} else
if {?Impact2} = 2.0 then {NETCOOL_HISTORY.IMPACT2} else
if {?Impact2} = 3.0 then {NETCOOL_HISTORY.IMPACT3} else
if {?Impact2} = 4.0 then {NETCOOL_HISTORY.IMPACT4} else
if {?Impact2} = 5.0 then {NETCOOL_HISTORY.IMPACT5}
...
...
...
////{@Impact5}:

with this i am able to display 5 lines on the chart. so what i need is, if the user wants only 3 lines in the chart, without removing 2 formulaes from the show values in line chart, is it possible to conditionally supress one or 2 lines if the user selects 0(zero) for 2 impact parameters. i mean {?impact1}=0 and {?impact2}=0 when he refresh the report. these 2 lines should not come on chart.

Any help will be appreciated.

thank you,
reddy.