A 3 month, 7 month, and 2 year old?

So here's my question. I watch a friend of mines 18 month old old during the day while my daughter is at school. I am due with my second in July, and will continue watching the 18 month old after a few weeks. Another friend of mine will have a baby that is 4 months older. They wanted to know if I could watch their baby with my baby and a toddler. The toddler is very easy going/easy. He will be 2 at the time and mostly plays on his own throughout the day. Do you guys think that it will be manageable? I think I can do it but would like some other opinions.