You could breed the offspring together and possibly produce an albino pinstripe. For example: pin het albino x het albino (doesn't matter which is which) has the following probabilities:
12.5% albino pinstripe
12.5% albino
37.5% pinstripe 66% phet albino
37.5% phet albino
However, you'll get better odds, and get 100% hets instead of phets, if you breed one of the pin het albinos back to their albino parent. Plus, if the albino parent is the female, and you get a male pinstripe het albino out of the first pairing, you can breed him back to his mother possibly the very next season, instead of waiting for one of the girls from the original pairing to grow up. Albino x pin het albino has the following probabilities:
25% albino pinstripe
25% pinstripe het albino
25% albino
25% het albino