You need to do it like the oldschool (classical) composers. Imagine the sounds and know which notes and timing they have independently of the real song tempo With just a piano there to get a better idea of how harmonies sound with each other, because imagination is not a full orchestra but just some cloudy ideas, but still… Yes, it can be done, and it needs experience and training, but then you are able to construct beats taking as much time for defining details as you like. For imagining beats it can be useful to translate the drum hits to vocal syllables, i.e. “Bop” for bassdrum, “Tek” for Snare, “Tik” or “Tssss” or “Trrrrrr” for…then find combinations of syllables that are like words, you can get inspirations by listening to the original breaks and traslating them to somekind of rhythmical babble you could rearrange or try to form new words from. Then you need to translate the single actions of the beat in your head to the tracker timeline, dividing it into blocks and then locating each hit can help, obviously proper line highlights are also useful for this.
As for keeping the original groove…in jungle style people would not use single hit samples, but samples with multiple hits in succession in original pace, keeping the original timing a bit. For single note hits, you could for sure extract a groove from the original break, and apply it to a mechanical set pattern, to make it live… I’ve sometimes tried finetuning a groove by hand using note delays, its real tedious work and you’d just want to make very few variations and then apply them to the whole song, but if you have good feeling for the lags and so it can be done. Rendering slice markers to phrase can extract timing of hits from a breakbeat you marked properly.






with creating anything out of it since I’m using my work PC for this, but it should give you a general idea and be good starting point.