Create phantoms to forward calls to the cell phones, add a system forward path to route DID calls to the phantom when the phone is in DND.
Phone isn't in DND, it rings. Phone is in DND, cell phone rings.
If the DID rings to a dispatch hunt group, create a system forward path to the hunt group. Apply to the station, immediate forward to the hunt group for DID calls only. Make sure the DND forward path is listed first, or it will be ignored.