I’m certainly no expert at particle flow, but isn’t this exactly what the ‘find target’ operator is for?
You make your particles follow the ‘goal’ object with the ‘find target’ operator and when they hit it you send them to a ‘speed by surface’ operator with 0 speed, ‘position object’ operator or something to make them stick?
I recall watching a tutorial where I was shown how to make particles stick to a deforming mesh so that is certainly possible. If the ‘find target’ operator does what I think it does, then it should work.
In my mind it sounds logical. 
I’ll see if I can test it tomorrow(today?), well after I’ve gotten some sleep atleast. 