3- 5 gear special gearset?
Yes its totally possible.  The single-cog version is one way to make a single-speed on a multispeed wheel.



The downsides are that you don't gain any lateral strength in the rear wheel because it is still offset, and that the single or fewer cogs are pressing into the freehub with far smaller area, so you're much more likely to damage your aluminium freehub.   See How to prevent freehub body damage?

In your case you want a couple of gears but not all of them, so you would fit the 3-5 cogs you want, and then pack the rest with spacer as per the photo.   Don't put spacers between the cogs.   Aim to have the cogs so the middle one is in the middle of the freehub, which will give the straightest chainline.

Then adjust the high and low limit screws on your Rear Derailleur mechanism.  Its quite possible they won't go in far enough, and you may need to find some longer screws with the same thread to do the job.