each magnetize pose should be numbered according to the number of V4's in a scene... you'll have a magnetize to v4, magnetize to v4_1, magnetize to v4_2, magnetize to v4_3, etc. Apply the appropriately numbered pose rather than, say, applying "magnetize to v4" on both. "to v4" on the first instance, "to v4_1" on the second, and on.

If you find this to be too troublesome see this free script by Dimension3D_

http://d3d.sesseler.de/index.php?software=poserpython&product=add_deformers