I think your goal is it to select multiple lines, click e.g. on settle and all selected trades should be settled. Based on my understanding this is not possible because you can select only one single line. This is defined in the ALV procedure (multiple line selection deactivated). Therefore the only chance to realize such a procedure is to write a report where you use the BAPI (e.g. for settle FX-Trades) BAPI_FTR_SETTLE.