Suction Cup

[Dong-Le-gnoD]

Hi folks,
I am working on simulation using a deformable suction cup to pick up a deformable object. At this moment, I've already had a basic setup, both the cup and object are using deformable properties from STLIB.

However, I was wondering that how do I attach the object to the suction cup after the collision. Could you suggest any idea for the operation?

I am thinking of 2 options:

1. Attach two object by the indices, but it follows almost the same as Using AttachConstraint to tie deformable and rigid objects together #2735 . I move the suction cup down with arrowkey, and press "m" to connect two objects together, but it does not look good and it will crash.
2. After collision, any pair of indices are attached to each other. But I am ensure how to do it?

Here are the code and meshes
deformable.zip

Thank you!