Parking lots for departments/offices within same Tenant

Hi all,

I am in the process of configuring the system for our company. We are using the Multi Tenant product, version 7.5.1.0. My question is regarding Parking lots for departments/offices. We are a property management company with multiple physical offices. I'd like to be able to configure the parking lot so specific slots are restricted to a specific office, i.e.:

Office 1: 701 - 703
Office 2: 704 - 706
Office 3: 707 - 709
etc...

Currently we have Yealink T27P phones. I'd like to be able to configure the softkeys on the phone in the following way for each office:

Example for Office 1

Softkey5: Park --> 700 --> Park
Softkey6: BLF --> 701 --> Park 1
Softkey7: BLF --> 702 --> Park 2
Softkey8: BLF --> 703 --> Park 3

The idea would be that when someone calls into the office and the staff needs to park them, they would hit softkey 5 to park the caller and Thirdlane would park the call at the first available slot between 701-703. The BLF would indicate where the call is parked. This works fine today in a lab environment with one office.. but once I add multiple offices I can't silo the slots to those offices -- or I just don't know how yet.

I read this blog (https://www.asterisk-blog.com/2016/03/30/setup-call-parking/) last night on "How to setup call parking". There's a section for Static Setup with Multi Tenant and Dynamic Setup for Multi Tenant that looks like it does exactly what I'm looking for.

It's my understanding that the current version of Thirdlane uses Asterisk 11.21.0. Based on this quote from the blog, "The cited references are for Asterisk 13 but most of the information will apply to Asterisk 11 with some alterations.", has anyone been able to set it up like what is described in the post? If so, could you expand on how you were able to get it working?

Another thought, which might be a workaround (and maybe not a good one), would be to setup each office as their own tenant which would include their own parking lot. The issue there would be that the offices wouldn't be able to 4 digit dial between each other. Is there a way to configure tenants to be able to 4 digit dial other tenants, i.e. create a trust between them?

Thanks in advance for any suggestions or guidance you all can provide.

Jason