If you have adapter notifications and adapter services then you will need to have two separate connections. Otherwise you may get strange errors about transactions and the like. You should also avoid having connection pools shared across different functional areas, even if they are pointing to the same database. The reason for this is that tuning the size of the pool becomes quite difficult if you have multiple types of usage of a pool. You are also unable to easily change the database settings for one without impacting on the other.
One approach that seems to work quite well is to have separate pools for each package , as your packages should generally be divided up according to functional area too.