Multi-sample player with random triggers and probability slider

Hi all, hoping you can help me out here. I have a set of eight samples, all varying lengths and all ominous and creepy. What I have so far is a set of looped sfplay all being triggered at the same time and looping immediately continuously. This sounds great and I'm pretty happy with the overall ambience of it, but to make things hard for myself the idea I had was that they would work well for a video game dungeon level. I want to make a patch that when toggled on it will randomly select to play some but not all of the samples, with a slider that dictates the probability of how many samples are triggered. So when the k-slider is low only a couple are triggered, and at full they are all playing.

I do want each sample to play to completion once it has been triggered, but not automatically start straight again unless the random probability has chosen it to.

I think I've taken a wrong step almost immediately by going to loop, so hoping someone might be able to help me move forward from here. I'll attach where I'm up to, but more than happy to start from scratch.

A full patch would obviously be awesome but really any help would be appreciated.