If they fail to pay, of course it is you who has to fork out the money to pay it as you are the borrower on record. If you continue to fail to pay, the bank will recall the facility and commence foreclosure proceedings, i.e. to auction off the property. Now, if the final bid is sufficient to cover the outstanding amount plus costs, etc, then all is good and the bank will close the file. Otherwise, the bank has the option to institute enforcement proceedings against you personally to claim what is due to them. If the amount is RM30K or more, they would most likely go for bankruptcy proceedings. Guarantors are normally left aside first as they would have to exhaust their remedy against the borrower first before going after the guarantors.

Even if you now come up with some side agreement between you and your friends, it still does not matter as you can't use it as an excuse when the bank comes knocking on the door in the event of a default. That side agreement is privy between you and your friends, and is of no concern of the bank. It is you as the borrower who would feel the full brunt of enforcement against you personally in the event recovery from the sale is not sufficient.

Honestly and with all due respect, I think you got yourself into a really unfavourable and seemingly unfair position. All 3 parties ought to have been named as co-borrowers.