Configuring two logback appenders independently

I might be asking something trivial, but what I've tried doesn't seem to work. With my "MAIN" appender, I want to log all "info"s everywhere, except in a third-party package (let's call it boring), which produces too many of them (so I look at warnings only). Additionally, I want to log "debug"s in my interesting package. This works fine with the following logback.groovy:

root(INFO, ["MAIN"])
logger("interesting", DEBUG, ["MAIN"])
logger("boring", WARN, ["MAIN"])

Now I want to configure a different appender logging one level more like

root(DEBUG, ["DETAIL"])
logger("interesting", TRACE, ["DETAIL"])
logger("boring", INFO, ["DETAIL"])

This also works, but when I put both together, it doesn't. I can imagine that this is caused by the fact that each Logger is either on or off for a given level. I'm aware that for the behavior I want, the loggers in the "boring" package must be on the INFO level (because of the DETAIL appender) and that the messages for the MAIN appender are to be filtered, but I can't see how to configure this.

UPDATE

I see I was doing nearly everything wrong. The line

logger("interesting", DEBUG, ["MAIN"])

says nothing like "set the level to DEBUG for the MAIN appender and the package interesting and below"), it does two independent things instead:

set the level to DEBUG for the package interesting and below
add the MAIN appender to the "interesting" Logger

This seems to be impossible without writing an own filter, which is fortunately pretty easy. I ended up with something like

root(DEBUG, ["DETAIL", "MAIN"])
// settings for the most detailed appender
logger("interesting", TRACE)
logger("boring", INFO)

appender("MAIN", ...) {
    ...
    filter = new MyFilter()
        .deny("boring", INFO)
        .accept("interesting", DEBUG)
        .deny("", DEBUG)
}

where deny and accept are my methods adding entries to MyFilter. The entries are evaluated sequentially, i.e.,

in package boring and below, everything with level INFO or below gets denied
in package interesting and below, everything with level DEBUG or above gets accepted
otherwise, in any package, everything with level DEBUG or above gets denied

Inspired by this question.