Is it possible to change DUAL ZONE AIRCON to SINGLE ZONE ? 2007 C4HDi

Is there any way to change the aircon settings from Dual Zone to Single zone on my 2007 C4 HDI ?

I'm tired of twiddling 2 knobs when adjusting the temperature.

I have Lexia, but haven't spotted anything in there. Apparently some car makers have ways of setting this from the dashboard, but I haven't figured it out.