Add maps from multiple Mapsource products?

Is it possible to add maps from different Mapsource products to a
MicroSD card inside an Etrex Vista HCx at the same time?

For instance, I own Topo 2008 and City Navigator NT. can I put data
from both of these on the same card?

Yes, I googled. Not much luck. Mostly found people wanting to sell me
SDmicro cards, Mapsource products, or Garmin GPS units. :-)

Thank you,
Frank

Okay, I found the Garmin pdf that told how to do this. Since my Topos
are covering the entire AT and my Navigator maps are covering the
entire Eastern US and Nova Scotia, is there any way to switch an
entire product on and off at one time, or do I need to turn off the
many, many segments individually?

Thanks again.

Yes, go to the page where the individual maps are shown and then
select MENU. That'll give you a few options: Showw all maps, Show
none, Show Topos, Show City Navigator. I don't have an Etrex HCx so
can't say exactly what button to push to select MENU, but it is
possible and shouldn't be too hard to find.