If you are installing 4 Six volt I'd not go with a bus bar (That is what the multi connector is called,, If you were installings six or 8, then perhaps.
Wire like this
Ground |-6V+-6V+|
. . . . . . .|-6V+-6V+|--RV
That is you connect each pair (you think of them as 2 pair) to make a 12 volt battery then parallel the two 12's using a pair of jumpers and take ground off one pair and hot off the other.
And I'd like to thank the powers that be for the PREVIEW MESSAGE function, Getting those two lines to line up would have been a witch without it.