Using ICPM for multiple upstream ponds

I am looking to model a stormwater basin with multiple forebays. There are two separate inflows, each being designed with their own forebay, and at a slightly higher elevation than the basin bottom. Separating each forebay from the basin will be a berm, containing a spillway/weir. Ideally, I'd like to model these as interconnected ponds - both forebays being modeled upstream with ICPM, and the downstream basin discharging elsewhere with a free outfall condition for tailwater. Eventually, the basin will fill up to the forebay spillway elevations, at which the forebay and basin would fill up together as one larger pond.
However, in trying to run this, I receive an error "One or more level pool ponds are connected to both upstream and downstream interconnected ponds". This error does not occur when I switch the forebays off of ICPM to free outfall.
Is it possible to model a series of ponds, with multiple upstream ponds using ICPM? I'm hoping there's a step I'm missing here, or a possible workaround if not. Thanks!