I have this requirement to be able to book appointments.

I have a list of 50 offices and people with one/more skills work at every office.

Based on the account address and skill required, I need to be able to view the calendars of everyone working in the nearest office catering services for the requested skill and book appointments based on availability of both client and service provider

Most of the apps I saw on app exchange are for sales agents to go to the customer and not for customers coming over to the office. The field service OOTB feature supports a part of the requirement. Is there any way I can achieve this through apps or configuration? Is visualforce/apex the only resort?