Scenario:
For each release stream, I have several teams that can potentially work on it, others are dedicated towards other streams.

Yet, i cannot assign these teams at the level of a release stream. I need to go through all backlog items and assign them individually. Since with epics (without child stories) I cannot assign multiple teams unless its on auto-calculate, it is impossible for these cases to assign exactly the right teams that are dedicated to my stream of work.

Suggested solution: Allow to set assignable teams for a release stream (this should be fully optional, if nothing it set, any team can work on any release stream). When this is set, the backlog items can be left to "Calculate" on the team field and the right teams get picked based on the preselection. Also, if I change it on stream level and dedicate another team to a release stream, this change reflects implicitly on all backlog items.