24 volt system question

To all:

This is somewhat a continuation of the charging batteries and charging them
discussion. Let's say you have two 12 volt batteries hooked up in series
for a 24 volt trolling motor. Can you use a two bank 12 volt charger
without disconnecting the two batteries (essentially temporarily removing
them from the series connection)? If so, I assume you hook up one bank to
one battery doing this for each battery.

I have not got this worked out in my mind, but it seems that if those two
batteries are hooked up in series, how do you charge them individually as 12
volts without disconnecting them?

Jeff