C++ MapVirtualFileEx - Creating multiple maps for faster access

C++ MapVirtualFileEx - Creating multiple maps for faster access

I am using MapVirtualFile to quickly access data from a file. However,
this is too slow. I guess it is because the file is huge (300 mb), and I
need to read from different locations (for example from the start of the
file, then from the end of the file).
I would like to know if somebody has any experience with creating multiple
maps from a file. Would that perhaps speed everything up?
I would then for example create 4 maps. One map that point to section 1 in
the file, the second map would point to section 2 in the file, the third
to section 3 of the file, etc.
Is that possible and would it make reading data faster?
My code is huge, and I would prefer thoughts about this before I invest 2
days just to find out that it does not solve my problem.
Thank you.