How to write subcircuits netlists in Spice with multiplicity factors?
That m is nothing but a convenient shortcut to adding several subcircuits/symbols in parallel. Internally, that's how the circuit is expanded/flattened. If your simulator doesn't have this option, then about the only alternative is to simply add, possibly ad nauseam, several subcircuits and connect them all in parallel. I don't know if m can be a float (as opposed to an int), but if so, then, obviously, you'll have to restrict yourself to a fixed number of subcircuits.