Using two different ld_library_paths at runtime

Question

I want to execute a c++ program that starts 2 sub-programs. The problem is, that one program needs another library path as the other program. So I have something like this: -_Parent program execution --->setting LD_LIBRARY_PATH-> Execute first child program --->setting LD_LIBRARY_PATH new -> Execute second child program

How can I achieve that (or isn't this possible at runtime?). Thanks in advance!