Collecting stats from multiple users

I’ve got a few subdomains that I have been collecting statistics from for the last few years.

These subdomains have always run as the same user, so running a cron job to collect the data was trivial.

Now I’ve farmed out each of the subdomains to its own user account.

I would like to continue collecting the stats data in one place, as one user via a cron job.

Not being a Linux-guy, I know little about su and sudo, but is there a secure way to have a single cron job running as USER_A access the domain logs of USER_B, USER_C and USE_D without introducing all sorts of security holes?

It strikes me as just asking for trouble.

Just curious. Thanks.