I had twins after having my DD1 and was on my own a lot. I tended to do the first feeds with DD in/on the bed with me and then jump in the shower straight after (always, always lay out breakfast stuff and everybodys clothes the night before). Then I juggled babies as me and DD1 had breakfast.
I painted, drew, did stories, played railways, barbie, glued, play doh at a big table so that I would always have everything I needed for DD1 in one place and didn't run around trying to tidy up the whole house.
I had a play gym, swing, rocker chair etc and would rotate babies from breast to one of them to lengthen the time they would be happy.
I let them cry sometimes. Sometimes, DD1 needed me, all to herself. And sometimes, she came first and they had to wait. They don't remember, she would have.
Bathtimes, I popped DD1 in the bath first and let the DTs kick, one at a time, nappy free, peeing everywhere as I tended to DD1. It was like a conveyor belt. If one vacated a position, the next one moved in.
Once I had dried DD1 and she was ready, I let her watch telly as I sorted the DTs.
She watched a whole heap more telly that I thought I would let her but, in the grand scheme of everything.......it was fine.....she got my attention throughout the day at different times. She learned that sometimes, she was priority and sometimes she wasn't and she learned that she wasn't plonked in front of the box to keep quiet.
It becomes a queueing system and you have to learn balance. Its the hardest thing because you want to give them all 100% but its fair.
Don't feel guilty. You have to share yourself and as long as everyone gets their bits of solo time, thats your best.