Super small potential wishlist item - I found the need to select multiple PRT Readers within a particle texture. There are plenty of workarounds though, like combining the PRTs with krakatoa (which is what I did), or using more than one particle texture in a composite map (which is what I should have done).
ironically it was exactly like this in version 1.0, but we changed it to single slot, i even can’t remember why.
but the script name of the particle system is still “sources”, not “source” 
Anyway, adding it to the TODO list.
Thanks for the suggestion!