Grouping recipients by domain

Are there benefits/disadvantages to grouping my recipients by domain?

If you group like recipients in the same domain as multiple recipients on the same message, it may make sending more efficient. However, the more recipients you have per message, the more 'spammy' the message may appear to spam filters, and the recipient domain's email provider may choose to rate-limit your inbound messages or just block them altogether for a period of time.