Enable users to select multiple cost codes for a single booking to allow cost sharing between departments.

Problem:

It is a common scenario that multiple departments want to share the costs of a single booking (e.g., a joint meeting with catering, a cross-departmental event). Currently, the system only allows one cost code per booking.
This means:
• Cost splitting between departments is not possible within the tool
• Users must find manual workarounds (e.g., internal recharging, separate bookings, offline coordination)
• Financial allocation becomes inaccurate and creates additional administrative effort
• Cross-departmental collaboration is penalized rather than supported

Proposed Solution
• Allow users to select multiple cost codes for a single booking
• Provide the option to define a split ratio (e.g., 50/50, or custom percentages per cost code)
• Alternatively, allow a fixed amount allocation per cost code
• Ensure the total always adds up to 100% / the full booking cost
• Maintain compatibility with existing cost code validation (location-based mapping)

Business Impact
• Cross-departmental bookings are a frequent use case across the organization
• Without this feature, cost allocation is inaccurate and requires manual workarounds
• Reduces administrative overhead for finance teams and bookers
• Supports transparent and fair cost distribution between departments
• Improves financial reporting accuracy