Insert new row after G and create a formula across

hello

Please find attached example
What i would like to achieve is that after every G in column A

1. Create a row heading C a shown in green
2. Have the above alphabet next to S e.g A copied next to C
3. Have (S-G) figure in the row heading C running across from column D till the end column

I might need a code as there are more than 1 sheet which requires this repeated process.

Thanks

Regards