[R] Mass 'identify' on 2d-plot

[Evgeniy Kachalin]

Hello, dear R-users.

I have 2-d dotplot with two variables: x, y. Dots on this dotplot are 
grouped in human-recogniseable areas. These areas are not round-shaped 
nor oval-shaped. They are free-form, but still recogniseable by an operator.

What is ability in R to graphically (per mouse) define some area and to 
select all the cases felt in it?

'identify' is OK for 5-10 cases, but what if cases=1000?

Thank you very much for advice.

-- 
Evgeniy Kachalin