[GrumpyDave]

You could use nested contexts. Make a top level context called "Computer". Under that make a sub-context called "Laptop" and another called "iPad". Assign tasks that can only be done on one or the other to the appropriate context. Assign tasks that can be done on either to the "Computer" context. Then when you're working you can focus on just "Laptop", just "iPad", or "Computer" to see them all grouped by context.

Personally I keep it simple and just put it all in a single "Computer" context.