Ian it "unfair" to leave one dog behind?

[FaintlyBaffled]

We have three dogs and have recently had behavioural advice for DDog3 which we are implementing at the moment. This involves walking her often and on her own, with so far fairly encouraging results.
The problem is that this now involves me doing three lots of walks a day as I otherwise end up leaving one of the trio behind. DH thinks this is unfair on the dog, I think it's unfair on the neighbours and the behaviourist poopooed DH for putting human emotions onto animals.
So now I am conflicted.
In decent weather and when I'm not at work then three lots of walks is rather pleasant, if it's pouring with rain, freezing cold and I have work then it's less appealing. If I could walk DDog3 first, then take DDogs 1&2 afterwards, then that would free up a good chunk of time for me. OTOH I feel bad that DDog3 won't get that she's already been out and will simply feel abandoned and left out (doubly unhelpful as we are trying our best to keep her calm and zen like)
Opinions please

Could you maybe walk dogs 1 and 2 separately? I know that's an extra walk but night it be relatively quick with them separate? This would prevent any feelings of guilt? Or you husbandcould just join you for the big walk so it's easier?

Can you pay a local teen to assist you with walks?

I'm walking 1,2 & 3 individually at the moment which is my problem. Previously I would have taken all three during the week, then DH and I would divide up walks in different combinations at the weekends.
At the moment it's too dark to walk any useful distance by the time DH gets home, though we're going to try and do a short walk before he leaves for work to take some of the pressure off.
No real possibility of help from a teenager as the bulk of the walking is done in school hours

It's fine to take 1 & 2 out while leaving 3 at home, if you approach it the right way.

Does 3 have any separation anxiety issues? If not, then you just need to find a way to make that alone time a positive experience. Kong full of peanut butter, maybe?

Not in the house who but she is a needy old hag
The thing is I don't want her getting stressed or hyped up as it's totally counterproductive when I need to wheel her out to practice being a properly functioning member of dog society.
Thankfully today was beautiful and I've busted my 15000 steps already

Hire the services of a local dog walker.

Don’t have more pets than you can care for.

Well that’s a helpful comment Stranger.

OP doesn’t have more dogs than she can care for....this is a recent and hopefully temporary thing. She’s caring for them all fine at the minute by walking all 3 separately....she’s asking whether it would be an issue walking two together and leaving the third.

Could you try it and see how you think dog3 is when you get back?

Try doing it but leaving the other dog at home after her walk when DH is there a couple of times so he can gauge if she's distressed/ even notices? If you feed the first dog at the end of her walk and go out with the others while she's eating then feed the other 2 when they come back but take the first dog into another room and fuss her she might not notice/ care?

Walk her first, before the other two, for slightly longer too so she's more tired, then feed her or leave her with a frozen kong whilst you walk the other two. I'm sure she would just sleep and would be fine for an hour.

Thank god that stranger is here with her sage words of advice. Now which DDogs should I rehome?