ltt

i think it is difficult to control in pop,you can do that in dop , there is sand solver.
and if it has to ,try interact node

maybe use the function instancepoint(),this function can return the $IPT,so you can control the scale,rotate…due to the $IPT ,just like copy node

i think maybe you can check the attribute which you need in collision node first ,then you can use the paramter of attribute in vop pop