[Freesurfer] Combined parcellation of the left and right hemispheres

Hi,

I've been working on getting a finer parcellation of the Desikan-Killiany atlas using mris_divide_parcellation. I was able to generate two annotation files; one each for the left and right hemisphere. I want to create a volume similar to aparc+aseg.mgz, containing the labels and indices of the ROIs from both hemispheres. I tried using mri_label2vol. However, this gives me two separate volumes for the left and right hemispheres. Is there a way to combine these volumes into one? Alternatively, can one generate such a volume form an annotation file that has information of both hemispheres?

Any help is greatly appreciated!

Regards, Varsha