I play PTW v1.21 but want to play another player on PBEM who is currently playing PTW v1.14. Is this possible?

If not, is it possible for me to have 2 playable versions of PTW on my harddrive, 1 being v1.21 (for my own use) and 1 being v1.14 (for PBEM games only)?

I currently have 2 copies of Civ 3 PTW on my hard drive (one as a backup graphics file) but is it possible to have them both playable? Especially as different versions?