have you got a good double pram? will ds sleep in the pram out on a walk? i used to put them both in the pram and walk around until ds2 fell asleep and then stop at the playground and get ds1 out and spend some one on one time with him while ds2 slept in the pram under a tree.
i also joined a playgroup so that i could basically sit and breastfeed ds2 and try to settle him while ds1 safely played with some other toddlers and i knew he was safe i.e.. locked in!!
it will get heaps easier, i promise. one day you'll be sitting here on bb like me while the two of them play with each other and you'll think its the best thing ever!