I use the Android btsync app to sync photos between my phone and my NAS which is on all the time. If I add another node (e.g. my laptop) which knows the secret for the photos folder, how will the sync take place? Will the Android app upload all the images twice, or will they go to the NAS which then syncs to the laptop, or what? Obviously, the second option is desirable as it halves the amount of mobile data used, is there any way to ensure that's what happens?