Toxic Rain gem in two slots

I'm building Toxic Rain Trickster following the guide at https://www.poe-vault.com/guides/toxic-rain-dot-trickster-all-content-passive-skill-tree-gem-links#wither-setup
It mentions having two Toxic Rain gems with different supporting gems each.
Questions is, do I need to assign 2 separate buttons for each of those Toxic Rain gems or will using one of them use all supporting gems?

You would need 2 separate button controls, one for each setup.