I would not. if your talking 'brifters' I think they may run $150+ for lowerend 7spd. you need a new RD, a 7spd FW (so you need to respace and redish your current wheel) or a new cassette style rearwheel, and 7spd chain.
if you have a higherend frame that you really love it would be doable but you have to weigh the expense of it.
__________________
“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk