Batch aim

# Batch aim
# Select objects, then target
from pymel.core import *
def getPiv(s):
    currentSceneScale = currentUnit(q=1, l=1)
    tempSceneScale = currentUnit(l = "cm")
    select(s)
    setToolTo('Move')
    piv = manipMoveContext('Move', q=True, p=True,m=2)
    return piv
    currentUnit(l = currentSceneScale)
def makeBufferGrp(s):
    cl = getPiv(s)
    p = listRelatives(s,p=1)
    g = group(n="{0}_bufferGrp".format(s),em=1)
    move(g, cl)
    oc = orientConstraint(s,g)
    delete(oc)
    if p:
        parent(g, p)
    parent(s, g)
    return g
sl = selected()
aimList = sl[:-1]
aimer = sl[-1]
for s in aimList:
    g = makeBufferGrp(s)
    ac = aimConstraint(aimer, g,weight=1 ,aimVector =[0 ,0, -1], upVector= [0, 1, 0], worldUpType="scene")