There are "Local Network: and "By Network" options that allow to just connect to the local network or just a b3
Andover Continuum, SmartStruxure Solution
By default, the RoamIO2 Bacnet Service Tool has "Local Network" and "By Network" options which may attempt to access all bacnet devices across the entire bacnet network depending on what is selected. This includes all controllers connected to a routing device (BCX/AS/ES). The amount of controllers and the size of the network can cause a long delay in bringing up controllers.
Ensure that the RoamIO2 firmware has been updated to V1.110002 or greater. This version introduced the "Local network" and "By Network" selections in the Bacnet Service Tool.
Download the Bacnet Service Tool and user guide(1.110003) (Download Center)