[R-sig-Geo] multiple ring buffer

[vikram ranga]

Dear all,
I am trying to make multiple ring buffers using points; I have created
buffers of different widths using gBuffer from library(rgeos) but this
does not solve my purpose. I want to have three different rings of
varying widths for each point.
gUnion is not useful in this case as point are close enough and the
boundaries of different polygons overlaps.

Can anyone suggest how to achieve this in R as I do not want to turn
to ArcGIS for it.

Thanks in advance,

Vikram.