A customer requests an addtional circuit (3 outlets) in a stand alone garage.

She has an outside 100 AMP disconnect at the entrance. From there the feeder goes direct to the oposite side of the house and terminates at a Ronk 100 AMP manual transfer switch (for a portable generator hookup).

EGC and all neutrals from the single house distribution panel and the stand alone garage distribution panel are bonded together inside the Ronk manual transfer switch. The house distribution panel and the stand alone garage distribution panel have egc and neutral seperate as required in each panel.

House panel is 125 AMP service. Stand alone garage panel is 100 AMP service.

I cannot find a code section on this.
Q - Can both these two distribution panels be bonded together (EGC and neutral) at the same location inside the Ronk manual transfer switch?
Q - If they can be does the 1st bond of neutral and ground at the outside service entrance disconnect (on the other side of the house) cause a problem by being a second EGC and neutral bond?

Thanks.