Saying the blessing on a talit gadol, while intending to cover all other talitot (whether talit katan or talit gadol), will cover:

• All talitot that you already put on.
• All talitot that you will put on later that day.
• If you go out of whichever building you are in when you say the blessing on your talit, you must say a new blessing if you put on a talit (even the same talit) in a different building.

Exception You may intend for the blessing NOT to cover other talitot.
Example You say the blessing over your talit gadol on the morning preceding Yom Kippur.  You may intend for your blessing not to cover the talit gadol that you will put on just before Kol Nidrei.

Note If you don't have a talit gadol, say al mitzvat tzitzit over your talit katan.

Note If you remove your talit gadol, go to a different building, and put the talit gadol on again, you DO say a new blessing.