( c ) under algorithm 3 ( multiple ) the ecb shall  ( i ) compare pairs of target2 participants » pm accounts to determine whether queued payment orders can be settled within the available liquidity of the two target2 participants » pm accounts concerned and within the limits set by them ( by starting from the pair of pm accounts with the smallest difference between the payment orders addressed to each other )  and the cb ( s ) involved shall book those payments simultaneously on the two target2 participants » pm accounts 