You can't 'home' in the classic sense to a 406 beacon as it is a burst transmission every 50 seconds or so but you will have a position to go to once that signal is bounced off the satellite and downlinked to the MRCC.
That in itself is no guarantee that you will be pinpointed immediately as the beacon message is in two parts and sometimes the second part (with the accurate GPS position in it) gets lost or disrupted, leaving only a coarse position (within 10nm or so).
Hence the need for a 121.5 signal (constant transmission) to actually home to.
Multiple beacons in the same location are not too much of a problem as you can home to the 'centre of mass' but if you have a lot of them spread over a larger distance (hundreds of metres say) then, unless you can spot the survivors visually (or thermally) you will have to start at one end and work your way through, switching off the beacons as you recover each casualty.
One other problem with modern 121.5 beacons is that they don't have the same helpful characteristics of the military PLB signal that many will be familiar with - that is a pause between each transmission that allows you to associate the audio with the needle indication and differentiate between multiple signals. The only option with the 'constant beep' beacons is to home to the strongest signal first.
So the answer to the question depends on the scenario - if all the survivors are in one raft then you don't need all the 121.5 beacons going off - if you have multiple people in the water then they should all have them on.