I'd leave the 5 in a single pot, pot on if necessary and then plant out in the garden. But it depends how you are going to plant them out.

Hello ... Another option, depending as MG says how they are to be finally planted out ... I would gently separate them WITH their pea pod, pot them on for a week or so in well-fed watered compost, and then re-plant out in each corner of a large pot or bed area with a climbing frame, lots of compost and lots of feed and water (pinch out the tips at about one foot to bush them out). Prepare the planting area well first, as sweet peas are huge feeders and need moist soil. Feed fortnightly, regularly dead-head as you are passing, and maintain moisture.