Should Mjällby beat Lincoln Red Imps from Gibraltar - in the two-legged tie that begins in Sölvesborg on Tuesday - they will face either Slovan Bratislava (Slovakia) or Iberia Tbilisi (Georgia) in the third qualifying round.
In the event of an exit against Lincoln Red, Mjällby will instead have the chance to qualify for the Europa League.
In the Europa League qualifiers, Hammarby - who first face Anderlecht - could face Dynamo Kyiv (Ukraine) or PAOK (Greece) in the third round.
If IFK Göteborg win against Tallinn in the Conference League qualifiers, "Blue and White" will face Cherkasy (Ukraine) or Gent (Belgium). For Gais, Valur (Iceland) or HSK Zrinjski (Bosnia and Herzegovina) await if they beat Nordsjælland.
