Not possible unfortunately would be my sense. If an employee asks for bonus as a pension contribution, that’s salary sacrifice. Smaller employers have been known to document things more advantageously.
The best bet might be to AVC for last year up to the max prior to 31 October and AVC for this year also.
e.g. 40 year old on €200k a year sticks €57,500 in (half for 2018/half for 2019).