Make some lines invisible in Time Scope

I attached a PDF format of a Time Scope plot. Is there anyway you can make the data not to be plotted out during the simulation (ex: the redline from 0 sec to 15 sec and the blueline from 15 sec on)? I was plotting 2 different outputs to the same plot but I would like to show only the data which is generated with the usagoe of the 'If Then' block.

Thanks.