1 pointUse subrules for "case" like functionality. Any common conditions that apply to all the rules in the group can be added to the parent rule, and then subrules can take advantage of the individual conditions you mentioned, while each has their own set of actions.
1 pointThanks. The action you want to select is the one for creating a new private conversation. For the sender, use the manual config and type the name of the account you want to use. For the message content, just use one of the available tokens listed at the top of the page.