Using extract info.
Here you stuck with the most common EDA tool portability issus, please try to understand what you want and what are your goals.
From your question, I understand you have your layouts in two EDA softwares, I know very well about Cadence, little knowledge about Magma. So from layout point of view, once you extract your ckt and pads. use the extracted netlist in spice simulator and set the proper stop and view list.
If you can use cadence, then its very easy using Hierarchy editor, but you said you are not allowed, so in spice simulator you have to manually set your stop and view list.
Hope this helps.