It is important to attempt to pin point the exact location in the wall,use a tincan or open ended container and listen in various spots like a stethescope. After locating the suspected location,carefully make a hole no bigger than the nozzle on a can of wasp stopper or bee spray. Apply a dose of spray,remove the nozzle and temporarily seal the hole with putty or even a paper napkin. Listen to the area again for different signs,louder buzzing could indicate the spray may have only affected part of the hive,a quieter area may indicate you have dealt them a blow.
After some time passes,reopen the hole and see if there is any activity ,if things appear quieter reapply another dose of spray.(USE PROPER VENTILATION WHERE REQUIRED) A small section of wall material should be removed,3"X 3",use caution and have some material handy to block it up quick,if necessary.Attempt to locate the hive if possible,spray again, if possible leave the room and go out and attempt to observe any fleeing bees.This will indicate where they are entering the interior.Make every effort to remove the complete hive as dead bees and larvae can create an offensive odor. Make repairs to the plaster,sheetrock or other wall material .