How to remove components from the frequency spectrum

Hi,

I have a signal and its spectrum and I would like to run dft and sndr/sfdr on it. However, I have a few spurs in the spectrum and would like to run the spectral analysis removing those spurs. Can I generate a new spectrum from the existing one but without the spurs or find sndr not taking them  into considerations? I know how to do it in Matlab, but have no clue how to do the same in spectre.

Thanks

Svilen