Hi
Dave your P103 unit can be "missused" to allow charging of 2 batteries from a single scource (charger) while giving some isolation between them. Altho I would add 2 resistors to give the diodes some protection in the event of a battery being totally flat (0V) when you start to charge. The resistors would be selected to limit the current to a safe value for the diode.
It is not an ideal situation charging batteries in parallel but it can be done (with care)
Michael
If you wish I can let you have a diagram of the requires circuit, it would need 2 diodes and 2 resistors
cheers Tom