First off, that question should be raised with your company attorney. If they say its legal and you can find their names via another way than the current company's contact list, then go for it. The trick as mentioned previously is what will the current company do if they find you are at the new company and taking their accounts. If its legal to do and your attorney assures you that you can survive any type of legal action they might bring, go for it. You might want to socialize it with a few folks you know personally to simply see if they are interested in moving their business. DO NOT tell them you are involved at all just simply mention you've heard there's some other players in the market and were curious what they had heard or if they had thought of making a move. Do it as if you are concerned to lose their business perhaps but you need market research before its worth making any jumps.
If however the only path forward you can identify is taking the current book of business from the current company to a new one...eh, you probably need to re-evaluate your plans. You will not grow if you cannot find customers without the current company's data.
If however the only path forward you can identify is taking the current book of business from the current company to a new one...eh, you probably need to re-evaluate your plans. You will not grow if you cannot find customers without the current company's data.