@mcplata
You can do as elektron , but its far less flexible on mpc. You need to set a sequence length that is a common multiple of each track Length you need. The most common is mixing multiple of 2 and 3 steps , its suite easy ( sequence of 12 steps/ 3 measures for exemple)
Starting from scratch
Define a sequence length that will fit your polyrhythm...
For example 15 measures with 4 steps/ beats by measure ( known as classic 4/4) = 60 steps , multiple of 4, 3,6 and 5 steps.... Antway Each step/ beats can be divided in 960 ticks , so you can record or write notes anywhere "in between " your grid. OK ?
Caution : what you call ticks in your post is called beats or step in mpc .
We imagine 140 BPM "techno compatible" tempo.
- tracks length :
In Main window, set track1 length to 1,2, 4 , 8 or 16 or ..60steps ( in this case 60 would be the same as default SEQ length)...
For our example , set length to 1 step
Put a kick each beat, giving you the basic "techno" pulse looping each step, 60 times in the sequence length
Set track 2 to 3 step/ beats length.
First polythmic effect ... Your track 2 looops 20 times ( 120 steps)while the track 1 loops on every beats
Put a sound on it anywhere you start polyrhythm
Set track 3 to 5 steps / beats length
It will loop 12 times before return to sequence start.. Put something on it its already strong polyrhythm on 1,3 and 5 basis
For fun, put track 4 length to 15 steps , looping 4 times , a cymbal or pad on this track will really mess around with others

So you see you can have in this example 4 differents rhythm in a simple sequence.... It needs to find a common multiple to the length you need.
In elektron and lot of others sequencers, track length is independent of sequence length so it can loop anywhere following the tempo, on any track ... But in mpc you need to find common multiple if you want your tracks to loop correctly on each length. So your sequence must be as long as the common multiple of each subdivision you need.
Please let me know if it helps when you try it... Less flexible , but with a sequence length of 999 bars maximum, you have strictly no limit to your polyrhythm.
Here is a link to a 60 steps polrythmic I made.
Its using 4 , 6 ,5 steps subdivisions
Not cool to listen or to dance anyway..
https://www.youtube.com/watch?v=UqkOryJexkU