How to Validate mcdvoice in Solidres?

I’m working on a Solidres reservation setup where I need to validate an external value related to mcdvoice before allowing a booking to be confirmed.

What would be the recommended way to implement this validation on the server side without modifying Solidres core files?

I’m particularly interested in knowing:

Which Solidres event or extension point should be used for custom validation? mcdvoice
How can I prevent users from bypassing the validation through a direct request?
How should the reservation state be handled if the external validation API times out or returns an error?
Can this be integrated with the existing payment and availability workflow?
Any guidance or example architecture for implementing this safely in a custom Joomla/Solidres plugin would be appreciated.


Best Regard,
Max Martin