Set limit for each ports of storge unit seperately

To implement the input and output priority of each port, a balancer must be used for each port.
However, for non-continuous input or output, using a balancer cannot achieve the priority effect well.
For example, the input from A is produced by the factory, and the input from B is imported. A should have the right to priority input because I need to maintain the operation of the industrial chain. However, the products produced by the factory are often discontinuously output, which causes the balancer to not limit B's input when A is not outputting, and eventually, the storage is filled with B's input, resulting in the inability to continue production.
This problem may be solved by building more storage units, but the complex industrial chain in the later stage leads to complex storage logic.
Therefore, I think that only when each port can control the limit separately can the input and output priority be truly realized.

or use balancers and smaller storages with limits ?