This appears to be the case. As long as I made absolutely sure to damage them all at regular intervals, they stayed on me. If I forgot about someone blasting me at range and got too far away from them, they'd wander off.
Side note: No, my tank can't survive this ride at +4. One AV at a time, sure, but I might not get it done in the 2 hour time limit. On the herding of them, even with avoiding Malaise and Numina, it just ends up being more than my mitigation can handle. Granted, I never popped One with the Shield as I plan to respec out of it, but even Malaise on his own was a rough fight due to all the psi damage, so I seriously doubt my current build would live long with all 15 beatin on me. Regardless, It's a fun test.