When you join a Yahoo group, such as JP1, there is an option whether you want you get messages by email or only via the web interface. You can also change that at any time after joining. I suggest you try the JP1 group again andjust be careful to select the no email option.

As Jim noted for that other group, the moderator of a group has the ability to override your "no email" decision for certain messages and it is normal for the moderator to force a few introductory messages that way one time when you join. Jim noted that the moderator of the sonyhs10 group abused that ability and sent too many and inappropriate introductory messages. The moderator of JP1 did not abuse that.

BTW, the pronto code shown for video7 was a signal you couldn't generate with your Producer 7 without JP1, so why do you "guess there isn't a discrete code for it yet", when someone already reported one and you ran a test which wouldn't have found it assuming they are correct?