[exim] How to do SMTP authentication for multiple users?

Hi all,

I'm configuring Exim for the first time and I'd like to set it up so
users 'joe', 'jane', and 'nick', are able to access the SMTP server
with password 'abcd1234'.

The following in exim.conf does not work -- apparently I am unable to
have Exim accept regexps:

fixed_login:
    driver = plaintext
    public_name = LOGIN
    server_prompts = User Name : Password
    server_condition = \
        ${if and {{eq{$1}{joe|jane|nick}}{eq{$2}{abcd1234}}}{yes}{no}}
    server_set_id = $1

This does not work either:

        ${if and {{match{$1}{joe|jane|nick}}{eq{$2}{abcd1234}}}{yes}{no}}

Only specifying a single name seems to work. However, I prefer not to
have all users authenticate with a single login:

        ${if and {{eq{$1}{joe}}{eq{$2}{abcd1234}}}{yes}{no}}      # this works

Apologies if this is a stupid question, but I've perused the docs,
searched on Google, looked up the FAQ and tried any other possible
syntax, and still cannot manage it to work. I feel there's something
obvious escaping me, but I cannot grasp what it is.
Thanks in advance,

L.