Merge Vertices at -next click-

I don't know if it is suitable with the blender rules, but I wish there was a merge function where I can decide witch point is the merging point of selected group of vertices. yes, here is merge at last or merge at first, but with them I always select tripple: first the group of the vertices, then deselect the desired point, then select it again and then call the function merge at last. Thats a lot of clicking. So my solution would be merge at next click. I select the points, call the function, then the nearest point to the mouse gets highlighted and after click all points go there.