[Freesurfer] Superior Posterior Insula and DLPFC measurements

Hello everyone, I’ve been having a hard time trying to figure out how to get appropriate measures of gray matter volume for both the superior posterior insula and the DLPFC. The atlases included in freesurfer don’t provide such information after the recon-all process is run. Is there a way to get accurate measures without having to manually label these areas for each subject? I’ve seen some answers on the archive defining the posterior insula as G_Ins_lg_and_S_cent_ins, but how can I isolate the superior posterior insula? Is there a way to create a new label based on a combination of pre-existing labels?

Thanks in advance, Guilherme.