You can't combine these tickets and still get the cheap price. Also is two different alliances.

Secondly, IB is unlikely to tag check bags to final destination when on separate tickets, so you need to pick-up checked bags at MAD and proceed to check-in counters of Avianca. Not the end of the world, but do make sure that you have sufficient time at MAD to do it (as I believe Avianca check-in counters close 60 min before departure). At least 2-3 hours, also to factor in possible delay of the BER-MAD flight, which can cause you to misconnect to the Avianca flight.

Alternatively, you can consider BER-MAD-BOG on Iberia and a cheap domestic flight with LATAM or Avianca, BOG to CLO. This will allow your bags to be checked through to BOG and leave you much less vulnerable for a delay of your initial BER-MAD flight (as IB will rebook you in case you misconnect). Then you pick-up the bags at BOG and proceed upstairs for check-in with LATAM or Avianca - really easy at BOG.