Worms

[3dogdays]

im a lurker who needs some help dealing with Tape Worms

I'm watching my cousin's dogs this week while she is out of town. One of them pooped in the house this am and when i went to pick it up, it had tape worms in it +o( . Im not sure which one of the dogs it was but i have narrowed it down to 2 as the other 3( one of hers and my 2) we're with me.

I have a couple questions and i figured you guys would be of better help than google.
1. How do i treat it? i think i've heard they have a treatment at the pet store but does that really work? Should i give it to just the dog who has the worms or all of them?
2. How do i keep the rest of the dogs from getting it?
Thanks in advance