Pasting (or merging) two elements of a column together

Question

I have two sources of clinical procedure billing information that I have added together (with rbind). In each row there is a CPT field and a CPT.description field that supplys a brief explanation. However, the descriptions are slightly different from the two sources. I want to be able to combine them. That way, if different words or abbreviations are used, then I can just do a string search to find what I am looking for.

So lets make up a simplified representation of a data table that I was able to generate.

cpt <- c(23456,23456,10000,44555,44555)
description <- c("tonsillectomy","tonsillectomy in >12 year old","brain transplant","castration","orchidectomy")
cpt.desc <- data.frame(cpt,description)

And here is what I want to get to.

cpt.wanted <- c(23456,10000,44555)
description.wanted <- c("tonsillectomy; tonsillectomy in >12 year old","brain transplant","castration; orchidectomy")
cpt.desc.wanted <- data.frame(cpt.wanted,description.wanted)

I have tried using functions such as unstack and then lapply(list,paste) but that is not pasting the elements of each list. I also tried reshape but there was no categorical variable to differentiate first or second version of description or even in some cases a third. The really annoying part is I had a similar problem a few months or years ago and someone helped me either on stackoverflow or on r-help and for the life of me I cannot find it.

So the underlying problem is, imagine that I have a spreadsheet in front of me. I need to do a vertical merge (paste) of two or maybe even three description cells who have the same CPT code in the adjacent column.

What buzzwords should I have been using to search for a solution to this problem. Thank you so much for your help.