If you had the actual wire manufacturer and P/N you
might find either they, or some customer has fitted a
transmission line model (whether compatibly with your
particular simulator, or not...). Seems that even wires
of the same class (like say RG-58) have a lot of detail
variations that alter the attributes (shield material and
construction, solid vs stranded core, choice of dielectric
material and diameter).
Now if you only "need to do simulation" and are not all
that worried about accuracy and matching to a real
piece of hardware someday, you can be less picky
about just how good (or even valid) the model is. Just
what (besides, say, the difference between a B+ and an
A-) do you care about in all of this?
If you can describe the cable then Googling "{cable_ref}
SPICE model" will turn up plenty for you to rummage
through. Then you get to port it to your simulator if
you're not lucky enough to find one with a pretty pink
bow on it.