Just wish to make sure of something: in the circuit below, it makes no sense to speak of "the voltage at \$B\$ with respect to ground" without specifying which ground we are speaking of, right?
Since, voltage at \$B\$ would be \$0V\$ with respect to to one ground, but \$9V\$ with respect to the other.
simulate this circuit – Schematic created using CircuitLab
That circuit makes no sense because connecting two batteries and grounds like that shorts out both batteries.
Both V1 and V2 have both terminals grounded. While a 9V battery would have 0V over it and heat up due to short circuit, in an ideal sense, you cannot have a 9V voltage source with 9V between terminals and simultaneously have it in a circuit which defines there will be 0V between terminals.
Your ground symbols are not different. They define the one and only ground and you can't have different voltages defined as ground.
