Are the two mini-bosses in Mech that have keys for the Cache of the Legion able to be tanked with a multi-shammy team? Am I going to need to get a real tank, or will a couple earth elementals be OK? I'm trying to schedule some time with my tanking buddy and don't know whether I should use him in Mech to equip my team with the TotVs, or if I can do it on my own later on.

Anyone have any success here with 4x/5xShammies?