Pinch them off at the ground, leaving just one.

Agreed. If you try to separate them you'll damage them, and if you let nature take its course you'll stress all the plants. The only way is to pinch off all but one and give that one the best chance of giving you fruit. One plant can produce several squash.

If you only want one pinch them off. But if you want more I have to disagree about separating them. In my climate all cucurbits are routinely sown inside and transplanted. They may well be slightly stressed but it does not hurt them in the long run. Today I will be planting out my Zucchini from cells.

If I understand the OP, she isn't planning to transplant these squash but leave them in the pot, which can surely only support one vine.

Right - I missed that bit. Yes way too many for one pot.