we have recently got a weiner dog and a pomeranian

Whenever we've brought a new pet into our family, the way that we are able to get them used to each other is to just give them limited access to each other until they get used to each other. So, we will allow them to be around each other when there are people around, but when we are sleeping or are away from home, we will keep the new pet locked in the bathroom. Then, as they get used to each other, we will start to leave them together more and more. This has always worked for us.

Initially there will be some kind of aggression but soon they will learn to get along. I had no problem when I adopted a dog which was disowned by my neighbours.The new entry will take care to see that it behaves.

I would say just give them time to adjust to each other again. Did they get along before? We have two cats that came to us as strays. The black one came first over the summer and last week a cute little black and white one came. At first the black one wasn't too keen on having someone steal her attention but now they are sleeping in the same cat box together at night. I think just have occasions where they have to be near each other and show them both some love and eventually they'll accept each other again.

Give them their own crate with a soft blanket in it so they have a private place to hide when they want to. Also, try to feed them at the same time and stick to a routine. Exercise them together as well. And watch the stairs. Weenie dogs cannot go up and down stairs. Even if the dog tries to and can, do not let them at all under any circumstances. If they are not spayed or neutered, do so, because that also diminishes rivalry.