If you have the root permission you can try this way.
* 22 * * * /root/sbin/allDomainsCron.sh Where allDomainsCron.sh contains your domains cron.php one by one:
#!bin/bash php /var/www/domain1/cron.php php /var/www/domain2/cron.php php /var/www/domain3/cron.php php /var/www/domain4/cron.php ... So you can ensure that only one cron.php run at a time.
If you would run the script once a day at 22:00 this code will do the work:
0 22 * * * /root/sbin/allDomainsCron.sh