Detailed questions about basic users, scheduling, and calendars

[teedub]

Hello!
I am curious if anyone can help me. 
We have 1 pro account that we use for standing board meetings. 
On rare occasions, other staff will use their own account to schedule a meeting. Those users are basic users that were added to the paid account. 

Is there anyway to combine every basic user added to the account's scheduled meetings on the main account?
I hope that makes sense. The easy thing to do is license everyone, but we don't use it enough to justify the extra costs involved. Any tips or tricks would be appreciated. 

TLDR: I want anyone who logs into the main paid account, to be able to see all the basic users in the account's scheduled meetings and vicea versa, it would be great for the users to all see the main accounts meetings.