Is it possible to assign staff to a task automatically, or assign a secondary email?

Hello, I have admin rights on our staff bookings page.
We have an internal mail system integrated with M365 Outlook and each staff member has a work address assigned to our company domain.

The problem arises from Booking's apparent inflexibility:

I cannot seem to add contextually separate availabilities for the same staff member. 
For example, I want to be available on premises 3 days a week for the hours 9:30am to 14:30. I will additionally be available for online appointments 2 days a week 13:30 to 17:00. 

Let's say I have 2 tasks, A and B. A is in-person and B is online.
When I assign staff to task A with hours for 9:30 to 14:30, then assign them to task B, adding 13:30 to 17:00, it universally assigns them those hours for task A as well, even though it is a separate task and they will not be available in-office then.

I could not figure out a way around this, so ended up adding a separate staff member, which then requires a second email. We cannot get additional emails provisioned, so they have to use a gmail account. Our internal mail server is unreliable when sending to gmail and sometimes filters our outgoing appointment emails as spam such that it doesn't reach gmail at all. I have personally tested this. 

I thought that maybe I could just assign our primary email to an "additional email" field on the secondary staff clone, such that our internal email would still be pinged, but it doesn't seem to be an option. Then I wondered if it would be possible to automatically assign the staff's primary account (to get the notifications) when their secondary clone was booked for online appointments. 

Ultimately I am just looking for a solution to this problem, no matter how it's accomplished, but would also like to see Bookings just allow that baseline functionality to begin with. It feels unnecessarily restrictive.

Thanks