The small crawlers in the red and blue area can be pulled separately from the black ones. i dont't know the exact linking of the mobs, but these 4 can be easily pulled in a 3+1 fashion.

these crocodiles are also not completely linked

For ease of use these crawlers willbe seperated into two groups of linked mobs. You can use CTRL+Left Mouse Button to force single select/deselect crawlers.