Frydek Help?

If I have 3 separate Frydeks each in 4 inch pots (not very root bound), could I plant them all into one pot to make a big, bushy Frydek? If so, what size large pot would I need? Would an 8 inch work? Thank you!!

not my photo, just for attention

If I have 3 separate Frydeks each in 4 inch pots (not very root bound), could I plant them all into one pot to make a big, bushy Frydek? If so, what size large pot would I need? Would an 8 inch work? Thank you!!

not my photo, just for attention