Copy/pasting helpful comment as an answer:
Note that there are TWO types of FOR subsystems. According to the documentation:
For Iterator Subsystem: Represent subsystem that executes repeatedly during simulation time step. Doc here.
For Each Subsystem: Repeatedly perform algorithm on each element or subarray of input signal and concatenate results. Doc here .
What you choose here depends on the kind of output you are looking for. This is a little vague from your explanation.
To me it looks like you want the second. That is, take in the 2 constant inputs and FOR EACH element in the 3rd input, read maps accordingly. The output will be a concatenated 5xn value for all the 3rd inputs together.
If this is not what you are looking for, let us know specifically with examples what output you desire. If you can include the sizes of the inputs and the expected outputs, it will be better to help as well.