I am running mixed level simulation combing behavioral Verilog AMS code with Spectre Netlists (using modelpath variable) and the only problem I have is the spectre netlist subcircuits behave like a black box; i can't view any of the voltages and currents within it. For example, say I was co-simulating a gain amplifier with a filter and the amplifier was a subcircuit of a spectre netlist. Say i wanted to view the voltage on a particular transistor within an instantion of amplifier, how would I do this?
Basically i cannot look at anything within the spectre netlist (subcircuits), I can only look at the inputs and outputs of the subcircuits I instantiate. Any ideas?

Unfortunately much of our schematics use 3 terminal devices and because progn isn't supported by the spectre netlister our spectre and verilog ams netlisters do not work properly (the fourth terminal of all the three terminal devices is being mapped to something like vdd! or vss! instead of Bn). Our  company uses our own netlister. I've worked out a fix (based on changing the spectre stopping view and changing the parameter  Bn to a  netexpression) but we have legacy issues with it that we are working out. So right now the best solution is to use our own netlister and  use modelpath to utilize the netlists.

We have used your solution to imitate progn behavior for Spectre netlisting. However, for AMS netlisting there is no field in the Siminfo for ams view for netlistProcedure so I don't think a custom netlist procedure can be used. The ams simulator also seems to say that this is impossible. Taken from the AMS Simulator manual:

For traditional Cadence netlisters, which are usually written in Cadence SKILL language, a SKILL procedure that formats instances can be named in the netlistProcedure field for a device. The AMS netlister is not written in SKILL and cannot use a customized procedure for devices. Specifying a procedure does not affect the formatting of instances because the AMS
netlister does not recognize the procedure. New fields provided in the ams section provide the mechanism for specializing device instantiation formatting.