Apologies if this has already been referenced elsewhere, or is already the case.
This might be prone to abuse. A malicious DT1 member right now can't unilaterally kick someone out from DT2, they need one or more other DT1 members to exclude a DT2 member. In your proposed scenario a
DT1 member could keep adding sockpuppets (or just random users who happen to exclude the targeted DT2 member) until they reach their goal.
That sounds familiar...