How to stop Agent from fetching headers of uninteresting Groups?

[nljlistbox2@gmail.com (N. Jackson)]

I use the Agent for reading news offline (because I don't have an
Internet connection for many hours of the day). I only read a
handful of news groups offline, but the Agent downloads the
headers for every single group on my agentised servers. This takes
about fifteen or twenty minutes every time I do `J s' because I
have very many groups on those servers (most of which I only read
about once a year). Downloading the actual news for the groups I'm
interested in reading offline only takes about a minute, so it
seems insane to download all these headers that I don't want.

How can I tell the Agent to not download even the headers for a
group?

Currently I have one Agent category for each of my agentised
groups. That is the "default" category and it is set to 0 (by the
Agent when it first set itself up). For the groups I want to read
offline I have group parameters that tell the Agent to retrieve
all messages (I have a `true' predicate).

It seems I need an Agent predicate that is more strongly negative
than `false', something like `not-even-headers'.

I suppose I might be asking the wrong question, since the Agent
predicates are to tell the Agent which articles to get, it must
have already retrieved the unwanted headers before it even starts
applying the predicates. So I need a way of telling the Agent at a
higher level not to even get the headers. But I don't see anything
useful in the documentation.

What am I missing?

Thanks.

Regards,
N.