Start point after loop point?

Is it currently possible to set a sample's 'loop start' marker to a place that's before the sample's start point marker? I can't see where/how atm?

Trying to start a loop so it it plays from a point that isn't the beginning of the loop.. Kind of like when you'd shift the steps of a 16 step sequence pattern to the left<< and all steps move but none leave the sequence. Changing its start point but without losing any notes. If that makes any sense...

Thanks