Unsubscribe a group from a package after reassigning

[Reinhard Tartler]

I reassigned bug https://launchpad.net/bugs/31357 from mplayer to
xserver-xorg-driver-sis package. I noticed that this bug did not
subscribe the bug contact 'Ubuntu X Swat', but kept the 'MOTU Media
Team' as subscriber. A therefore subscribe the 'Ubuntu X Swat' manually.
Shouldn't this happen automatically when reassigning?

Is it possible to unsubscribe the 'MOTU Media Team' from this bug? how?

Greetings,
	Reinhard