Ah, yes.
A truly little baby will listen to everything, especially if he is too young to reach for the book. Yes, he might wriggle, or cry, or drool excessively, but you can read pretty much whatever the bigger child wants without interference.
A baby who can grab, will. The bigger child won’t like that. You probably won’t like it either. Can you have a second, or even a third, book at the ready? The baby will probably be content to hold a book for a little while. Be prepared to swap.
Also, a baby learning to grab may not be able to hold the book for long. The book will drop. Soon, the baby will reach for the one you’re reading. You need to be part octopus, right?!
Snacks might help too. A baby mouthing a bagel will get the audio portion of the shared reading and a nutritional extra. Have two bagels ready since both want what the other is having. 
And what about lift-the-flap books, you ask? Or touch and feel interactive books? The flaps will flap and the bunny’s fur will be touched. Learning to share and take turns takes time. In the meanwhile, the flap may get torn off, and sticky fingers could ruffle the bunny’s fur. The bunny might have a bald patch, but onwards!
Lois Ehlert (a beloved illustrator, most famous perhaps for Chicka Chicka Boom Boom, written by Bill Martin Jr. and John Archambault) often includes words and imagery for different aged children. Remembering her own family of older and younger siblings, she offers extras for the bigger ones. All of you will learn something from sharing her books.
