You can probably get them to divert HD over to your ground station. Then you only need to run out of the HD building on Saturday. It's not ideal, but they will make it work to help encourage the overlap. At the very least I'd recommend building relationships with the HD contractors and getting tentative deals in place now so you're prepared if/when it happens.
I think part of a forced combination will be the elimination of the stupid VRP program they use at HD and FedEx will just load all the HD anyway. This would eliminate the need for the HD side of the belts and the stand alone HD buildings. If you just step back and watch a HD building during the sort it is an amazing model of inefficiency. It is strikingly stupid how they do things.
HD was supposed to be a stand alone division when it started. Just months into HD, fedex unilaterally changed plans because the growing pains were expensive. They sold HD to day one contractors based on the plan to have small vehicles delivering only to residential locations. I was told that I could set my own hours, and work part time, as long as I serviced my zip code, and could contract for more zip codes if I wanted to. HD was sold as 'perfect for retirees' who still wanted to work part-time.
That never happened. I was only looking to work 20-30 hours a week, and contracted for 5 rural zip codes. Instead, they 'requested' that day one contractors cover more area than they had agreed to until 'things got up to speed.' I guess things never got up to speed because I was told that I had to work 10-12 hours a day or more or 'face risking my contract' even though I fully complied and had a 99% service rate, even in the expanded areas I had never agreed to serve.
I ended up working an average of over 11 hours a day for 5 years until I finally got sick of the bullying. In the end, they claimed that they could demand 'full use' of my vehicle, no matter how many hours it was, instead of letting me determine 'full use' as the law would require based upon the idea that vague terms have to be interpreted in the light of the party who did not draft the contract. They even tried to convince the judge in the UI appeal that they could require me to work 24 hours a day, and require that I hire someone if I didn't want to work 24 hours a day.
I won an unemployment case, a case challenging the validity of the arbitration clause, and a class action case. I think I am more familiar with the laws than any one of the fedex supporters on this site.