How to implement many to many nova resource without building custom tool

I am currently building a timetable generation system, I have these models below which are Subject and Teacher as the two main models with their nova resources, I have created a pivot model SubjectAllocation (has a nova resource) with a pivot table subject_allocations with fields teacher_id and subject_id. I would like to be able to use SubjectAllocation nova resource to select a teacher and allocate multiple subjects to this teacher but currently, I have no lack of it. Tried pulling in this package dillingham/nova-attach-many to attach to the SubjectAllocation model and this package to pick teachers records sloveniangooner/searchable-select but it cannot store data in the pivot table.

Any suggestion on how I can make it work or a better solution, would appreciate very much