Simulink: Offset from file data in time

I am trying to compare some signal processing operations in Simulink. I am processing data from two from file blocks. The problem is that the signals are offset in time from each other. I can certainly fix this in Matlab when I create the .mat file, but I was hoping to do it in simulink. I tried the time delay block, but it slowed things down way too much and did not seem to do what I wanted - I sometimes need negative offsets.