MKVMerge GUI: How to Join two AVI with two SRT files (CD1 - CD2)

Hello,

I need to join two AVI files with two SRT files.

• AVI file is called CD1.avi with CD1.srt
• AVI file is called CD2.avi with CD2.srt

The problem is that CD1.srt starts at minute 6 and CD2.srt file starts at second 56 (which is for the CD2)
How is it possible please to join CD1.avi with CD2.avi while CD1.srt is appended to CD1.avi and CD2.srt is appended to CD2.avi


Thank you greatly for the help!