Three person mechanic

[FUBLUE]

Here's one from a summer game I was watching. Talked to several peole about it, but not sure you all y'all have heard about it.

ASA 18U Fastpitch

R1 on Third, R2 on First. Two outs. Tied game. Three person system. All umpires are where they are to be (U1 between 1st and 2nd, U3 in fould territory at third, Plate at home--thankfully).

On the pitch, R2 attempts to get caught in a rundown in order to score the run. What is the proper mechanic for covering the rundown? Does U1 take it solo? Does U3 help, leaving Plate umpire to cover R1 at third? Does Plate cover backside of rundown and U3 rotate home? (Hey, I'm just throwing out options here)