[exim] How multi-recipient messages are handled?

Hi, I have a question about handling messages with multiple recipients in Exim.

I want to run something like rspamd and apply per-user spam filtering,
which means multiple recipients might have different spam scoring
results or different white/black list results on the same message. I
know it depends when it's done, like during the SMTP process or after
accept.

I use Postfix now and I can force it to reply with 452 4.5.3 error
("too many recipients") if there are 2 or more recipients so rspamd
milter will never have multiple recipient messages but this is bad
behavior and frowned upon I believe.

How does Exim handle this situation, what is the recommended approach
taken by Exim administrators? I appreciate links, opinions, tips.
Thank you.

Aki