Domain and Subdomain Share Calendar?

[jcimb]

Still not sure after reading the forum whether I can have a domain and subdomain share one database.
Main domain: courtsandridges.org
Subdomain: swimteam.courtsandridges.org
Calendar's been set up and working for quite a while on main domain. Would like to access calendar now via subdomain.
The community has a swim team, and some events are to be displayed on both the main site and swim team site.
I've tried modifying calendar.php's URL path and modifying the requires: require("http://courtsandridges.org/calendar/calendar.php")
or
require("/var/www/vhosts/courtsandridges.org/httpdocs/calendar/calendar.php")

The only result I get that is not a white screen and is close to a calendar is with this:
urlPath="/calendar/"
and
require("http://courtsandridges.org/calendar/calendar.php")
even though I read that the require is not supposed to specify an absolute path.

Here is the page I'm testing with:
http://swimteam.courtsandridges.org/st_calendar.php

Version 6.3.29 ionCube

Thanks in advance!