FWIW, I spent some time trying to figure out how to do this by using a "mask". The Farbwerk360 does not know how many LEDs are connected to an RGBpx port, it only knows what you tell it. You did not specify what fans you have, but based on your picture, I think they are Lion Li Uni-Fans SL, which I think have 16 LEDs on each side. Assuming you are only interested in the LEDs you can see, 5 fans x 16 LEDs each is 80 LEDs total, which is under the 90 LED per RGBpx port limit. What I mean by a "mask" is having the Laser effect play back, but set both colors and the background color to Black. If you do that, the LEDs receiving this data will not light up. Spoiler Alert - I don't think what I have suggested below will actually work, but it may inspire a solution that does.

I was thinking you could set up 3 LED Controllers in Aquasuite - 1 LED Controller on RGBpx port #1 for Fans 1 to 3 and 2 LED Controllers on RGBpx port #2 for fans 4 and 5.

Port 1 - LED Controller 1 – Start at LED 1 (Fan 1 LED 1), stop at LED 80 (Fan 5 LED 16). Set this LED Controller to the Laser effect with the colors and speed that you want. In reality, there are no LEDs from 49 to 80, but the Farbwerk360 does not know that.
Port 2 – LED Controller 2 – Start at LED 1 (Fan 1 LED 1), stop at LED 48 (Fan 3 LED 16). Set this LED Controller to the Laser Effect at the same speed, but with both colors and the background color all set to Black. This is the mask.
Port 2 – LED Controller 3 - Start at LED 49 (Fan 4 LED 1), stop at LED 80 (Fan 5 LED 16). Set this LED Controller to the Laser effect with the colors and speed that you want.

When playback starts, RGBpx port 1 will start the Laser effect playback (with colors) on fan 1, then fan 2, then fan 3. It will continue to output data to LEDs 49 to 80, but there are no LEDs 49 to 80, so you will not see anything, but it will still be running.
When playback starts, RGBpx port 2 will start the Laser effect playback at LED 1 and run to LED 49, but since both colors and the background are set to black, Fans 4 and 5 will not light up.
When it gets to LED 49 (Fan 4 LED 1), the third LED Controller will start playing back on RGBpx port 2, sending the Laser effect (with colors) to fan 4, then fan 5. While it is doing that, RGBpx port 1 is still outputting the Laser effect, but it's going nowhere because LEDs 49 to 80 do not exist. When both RGBpx ports get to LED #80, the effect will start over.

The problem with this plan is that for RGBpx port 2, Fan 4 LED #1 is not LED #49, its LED #1. I think this would work if you connected a strip of 48 LEDs to RGBpx port 2, and then connected fans 4 and 5 to the output of the 48-LED strip. Then Fan 4 LED #1 would be LED #49. The LEDs in the 48-LED strip would never light up, they are just there to offset Fan 1 LED #1 to be LED #49 to the RGBpx port. I still think the idea of an LED Controller outputting black to use as a mask could work, but Aquasuite does not provide the ability to add an offset to the LEDs. I am either close, or this is a dead end idea. I decided to post it anyway because maybe you, or someone else on the forum, will read what I wrote and figure out a solution.

Aquacomputer did a nice job when they rolled out the RGBpx platform, but it is rather limited in what you can do with it. One of my pet peeves is that there is no RGBpx port sync between devices. I learned this the hard way when I installed 2 Farbwek360s. There is no sync between the devices. A few years ago they said they were going to release "RGBpx Fusion" with port sync and a bunch of new features, but they never did.