Crystal Reports Conditional Percentages and summation

Message

     Hi all, I have this data:
media        May                 Jun
TV Total     672,798.50     567,990.00

Rad Total   752,063.00     345,900.00

and i want to be able to achieve this:

ETISALAT - Group header

media        May                 Jun

TV Total     672,798.50     567,990.00
Sov%        98%                62%

Rad Total   352,063.00     645,900.00
Sov%         34%               64%

GLOBACOM - Group header

media        May                 Jun

TV Total     134,000.50     567,990.00
Sov%        2%                  38%

Rad Total   652,063.00     385,900.00
Sov%         66%               46%

if you notice, you find out that the percentage of 'Tv Total' for ETISALAT and GLOBACOM all add up to be 100%

I tried writing a formula for the months separately using this:
if ({stp_GetShareOfVoiceReportByValue_sel;1.Media} = "TV Total") then
{stp_GetShareOfVoiceReportByValue_sel;1.May} % Sum ({stp_GetShareOfVoiceReportByValue_sel;1.May})

but what i noticed is that the sum({stp_GetShareOfVoiceReportByValue_sel;1.May}) is getting the sum of all the data in may and not only the sum when Media = 'TV Total'

hence if i do an addition of the 'TV Total' sums for may, it should give me = 806799, but instead it gives = 1810925. 

Please any help will be appreciated