Answer: Don't worry about separating these plants. The only concern is if you plan to save seed for planting next year. Cross pollination does not affect the current year's fruits--only the seeds. (This might be a concern if, say, you were planning to harvest pumpkin seeds for roasting.)
However, if you compost the plants and some of the seeds sprout, you could have some strange gourd/squash mutants growing out of the compost pile! But there's no need to worry about this year's crop.
Q&A Library Searching Tips