Need is a strong word. There are various technical solutions to solve this, but it also depends on various factors. If you can direct B2B traffic to a separate page, it opens your options significantly. Having a dedicated portal has its perks, but it seems you'd rather avoid the extra overheads. Having a separate website is certainly a possibility, but once again it seems you'd rather avoid it.

The thing is, B2B is radically different from B2C. Retaining the same website will limit how flexible you are towards those clients, and if they are not demanding, it might make sense to proceed. I'm afraid that's the best I can say without further details, so I hope you found this helpful. Do reach out if you want to discuss specifics though.