Excel Buffer expand

Hello Guys

I will slowly despair... I have a problem. I need to expand the "Excel Buffer" with a function with 2 parameters. First parameter "From Row" second Parameter "To Row". Then i need somehow to Delete all Rows between this 2 Parameters. Somehow i have tried with multiple DotNet's but nothing works!! It should be connected with the Worksheet .net used in the Excel Buffer.
It can't be that hard

can you guys help me?

best regards