Erik, check this out.

This is what I set up for our company. I set a DID to point to Tenant 4 vm. recorded greeting such as " thankyou for calling our conference call line. Please enter your 4 digit code now."
Participant enters code(which is really just a DN) and is connected to call.

Go to System Parameters, Function Access Codes. Scroll down to Meet Me Conf. No. Program all 5.
Call the DID and enter one of the codes to test.

We have had this setup for 4 months and is working great! Each time someone needs to make a conference call, I program a new code for that call. Users think the code only works for their call at the assigned time.

This is great for keeping Conference Calls secure.

Keep in mind:
-Only 8 OUTSIDE parties can be involved in one call.
-If you have a limited number of outside lines, Keep tabs on how many outside parties are in each call at one time.
-MUST HAVE A SOURCE 1 MODULE FOR THIS APPLICATION ON VERSION 7 AND BELOW.