VT7600 with TAC MNB70 controller

We are trying to replace some old Carrier master/slave thermostats with the VT7600 thermostats. Due to our current 'energy managers', we need the scheduling functions to be as simple as possible. I would like to use the VT7600A1000 thermostat (Bacnet version) in the 18 classrooms, connected to a TAC MNB70 controller which will have a Graslin timer connected to a DI. We will also have a spring wound timer connected to a DI.

When either DI is closed, it would signal the MNB70 to start sending 'occupied' commands to each of the VT7600 thermostats through a series of sequence blocks and BV variables. I hope this is making sense. We really don't want to spend the money for a UNC or MNB1000 plant controller since our 'energy managers' will not be able to program either of these.

Will this work? The communication bus is already in place...