I'd suggest having the dogs meet in a neutral area, preferably a low stress place neither dog has ever been - like a park - and just keep them on leash and do a few "fly-bys" where you let the dogs sniff each other for about three seconds and then walk away. PRAISE PRAISE PRAISE if they're friendly, but walk away if they start showing they're tense or stressed. If you can get their attention on you while they're sniffing each other, that's a wonderful sign. When you can do this consistently, then maybe let them off leash in a neutral area (I like empty tennis courts). If they're still not comfortable with each other when you have to move in and they have to live together, try to keep them separate at all times unless you can give them 100% of your attention. Just keep in mind that IF dogs are aggressive to each other once, they are much more likely to be aggressive again.... but if they are never aggressive and you can always prevent aggression, they are much more likely to learn to get along.