[colicoid]

For complex juggling back and forth kind of tasks I keep a log in the notes field.

If the calls are to the same people you can set up a @people context with sub contexts for all the persons you most frequently call.

I also think you should not use projects as you do now, but use contexts instead. The calls you make/receive must be part of some kind of greater scheme no?

You can use a naming convention with indicators (like you have now lw/ret) in the task names. Instead of creating new tasks you can change the indikator. (Might be good to keep log in notes field if you do this).