ugadog99, what you need to do is better organize your music library, having multiple libraries is not necessary to do this.
First you'll want to create some folders in iTunes, one for each user. For simplicity, I'll call them "mom" (for yourself), "dd1" (for DD1), and "dd2" (for DD2), but you can call them whatever you like.
To create a new folder you:
1) Start iTunes (iPod not necessary for this step)
2) Choose the File menu (top of iTunes) and then choose New Folder.
This will create a folder under PLAYLISTS named untitled folder, you can just type in the name you want. If the folder isn't automagically selected after being created just keep selecting (usually from not being selected a double select/click is required here) it until it highlights blue instead of black and type the name.
Once all three folders are created, then have each person do the following:
1) Select your folder
2) Choose the File menu (top of iTunes) and then choose New Playlist.
3) Place the songs you'd like into that playlist.
4) Repeat multiple times for as many playlists as you'd like.
At this point each person should have their own folder that contains their own playlists which contains the music that they want to listen to and have on their iPod.
Once this is all set, each person needs to take their own iPod and do the following:
1) Connect your iPod, make sure iTunes is running (if you're doing this all at once it already should be)
2) Wait for the iPod to finish syncing (wait for "iPod update is complete" at the top")
3) Under DEVICES select your iPod
4) Switch to the Music tab
5) Make sure Sync music is selected
6) Select Selected playlists: - this will cause the list of playlists to now be selectable
7) Choose the playlists you want on your iPod (presumably the ones you created earlier)
8) Hit Apply
9) If your iPod doesn't sync after hitting Apply, then right click on it under DEVICES and choose Sync
10) Wait for the message "iPod update is complete" at the top"
11) Right click on your iPod under DEVICES and choose Eject
Once your iPod stops flashing "Do not disconnect." you can safely disconnect your iPod from your computer and pass control to the next person.
Now each iPod shares the library, but each has it's own music. Steps 9 through 11 are very important, pay close attention to them.