Making an aggregated factor variable from an existing one

Hi,

This is quite simple data manipulation task and I need help for it. I 
want to make new factor variable that is an aggregation of an existing 
factor.

This works as I intended:

X[Y == "original label"] <- " new label"

How to make following work then (to make coding more convenient):

original.labels <- c("ol.1","ol.2","ol.3")

X[Y == original.labels] <- "new label"

Cheers,

Antti