What key would a piece in Lydian and another in Dorian go to typically?

I have 2 pieces one in Lydian mode the other in Dorian mode, typically when in a major key you go to the dominant of the piece in the B section but I'm not sure what key is appropriate to go to in the B section of these pieces

What is most common?

Don't compare tonal functional music with modal. Nothing in common.

If you have a section in Dorian and want a change, you can go wherever you want: other mode, tonal, atonal... The result will depend on the coherence and transition between parts.