Can I use different calendars for each bot?

You can by setting up another account as a teammate.

Calendars work on an account basis. That means you can take appointment in one calendar per an agent, thus if you want to use different calendar you can add other agents and connect the other calendar to them.

How to use another account for this.

1. Invite a teammate using a second email you own.
2. On your second account, connect your other calendar.
3. Open up any bot you want to use, add an appointment object then select which calendar you want to take appointment in. 

You can use different calendars with each appointment object in the same bot.