The two connections available in the OBP Portal can be used simultaneously with no impact on the EU Hub side. A connection detail is composed by the Organisation Type, the Organisation ID and the Client ID and should look like this:
(D stands for Parallel Distributor and M for Original Pack Manufacturer)
Therefore both connections will be recognized as being part of your OPB Portal - as the Organisation ID will be the same and the mean from which the EU Hub will recognize your company - however it is not strictly necessary to have two different connections to the EU Hub. This means that the EU Hub will accept for instance Master Data from one Client ID and Product Pack Data from another Client ID - as the Organisation is the same.
In any case, what the Hub accepts can be restricted by OBPs Connection Providers - we know that the EMVO Gateway for example - because of the system's restrictions to decrease the risk of certain exceptions - does not allow an OBP to upload Pack Data of a Master Data that the EMVO Gateway does not recognize as being uploaded by the OBP.
With respect to other Gateway Provider's Solutions we do not have any insight therefore we would kindly ask you to contact them via their own appropriate means.