[exim] Thought exim did this by default..

I thought exim would make multiple delivery attempts over a single
connection by default..

so say for example:

exiqgrep -r @gmail.com -i
1LrZji-0006cD-Ci
1LrZkm-000PSH-QI
1LrZoV-0000ur-EI
1LrZqm-0002df-5b
1LrZwH-000Pax-Td
1Lra0i-0003KI-MB
1Lra2g-000KKM-Sd

These are messages destined for '@gmail.com' if I were to manually
attempt a delivery (-v -d -M 1Lra2g-000KKM-Sd) it will deliver that one
email only..

What is the setting that says 'attempt to deliver all emails destined
for "domain" over a single connection'..

(if that makes sense.. )