Need help in looping condition

Hi Gurus,

I am trying to write a loop condition in my script logic to generalise the below logic.

XDIM_MEMBERSET ACCOUNT= Conv
*XDIM_MEMBERSET PRODUCT=BAS(CBS)

*WHEN DISTRIBUTOR.ACCOUNT_GROUP
*IS L01

*REC(EXPRESSION=([PRODUCT].[C155K01] +[PRODUCT].[C30K01] +[PRODUCT].[C25B01] +[PRODUCT].[C25B02] + [PRODUCT].[C30C01] + [PRODUCT].[C30C02] + [PRODUCT].[C50C01] + [PRODUCT].[C65B01]),PRODUCT = CB_LO_DZ,ACCOUNT = Sales_Qty)

*ENDWHEN

Now I am having another product group set with more than 70 members for a parent. Please suggest me a best way to write a loop condition. Is there a way to write like below

For %C% = BAS(XYZ)

PQR=PQR+%C%

*NEXT

Please help me in this.

Regards,

Praveen