Hi Karsten, thanks for your reply.
A quick note to say with regard to “Personally I’d be concerned whether there are privacy implications to managing contacts belonging to two companies in one portal. You might want to check this with a legal professional.”
The database is mine (not of my clients), I own and I keep it in respect of the GDPR.
With regard to have two portals: you are right the best is to opt for a third party integrator.
Many thanks again!
Claudio