I had a problem with robbing from a weak hive (a failed split) that was in my back garden a few years ago, they needed time while the new queen was establishing herself.
The advice I had was to feed some fondant in the evening and drape a large sheet over the hive. Hose the sheet through the day to keep it moist.
I used a huge old curtain from a bay window and watered before work, pop home at lunch, again after work - The thicker material kept it moist longer. A few bricks stopped it blowing away.
Leave on for a week, but keep sheet moist.
Your bees will eat the fondant and use the moisture from the sheet, and can take poop flights in the cavity under the sheet. If any of your bees do escape from under the edge of the sheet they should remember the entrance exit ok if you don't disturb the sheet too much. I think mine just took the moisture as a "oh it's raining, lets not fly today".
The robbing bees will be confused by the sheet, avoid the moisture and give up. Reduce entrances on other hives to avoid them becoming targets.
It worked, but you have to resist the temptation to keep lifting the sheet to check on them.
Yes, once upon a time I was allowed to keep my bees in the garden...