Additional Function For The Replace Feature

The replace feature works by keeping the beginning frame of a clip and cutting off the end up to what the space allows. But in certain instances the end of the clip is more important than the beginning. So I want to keep the end of the new clip in that allotted space and the start frame can be cut off at wherever it needs to in order to fit. Can that reverse function be added? If it could be done, then maybe the shortcut Shift+R could be used for it.