In GFF3, annotating more than one protein-coding gene (i.e. polycistronic) contained in a eukaryotic mRNA Below is an example of a simple GFF3 file:

1   T1  gene    3631    4605    .   +   .   ID=ATNG01010
1   T1  mRNA    3631    4605    .   +   .   ID=ATNG01010.1;Parent=ATNG01010
1   T1  exon    3631    3913    .   +   .   ID=ATNG01010:exon:1;Parent=ATNG01010.1
1   T1  CDS 3860    3913    .   +   0   ID=ATNG01010:CDS:1;Parent=ATNG01010.1
1   T1  exon    3996    4276    .   +   .   ID=ATNG01010:exon:2;Parent=ATNG01010.1
1   T1  CDS 3996    4260    .   +   2   ID=ATNG01010:CDS:2;Parent=ATNG01010.1
1   T1  exon    4486    4605    .   +   .   ID=ATNG01010:exon:3;Parent=ATNG01010.1


My question is: if we found another coding sequence (encoding a different protein) range from 3752 to 3904, how should the GFF3 be formatted? It seems to me that the GFF3 file can only allow one protein-coding gene per mRNA. If not, could anyone show me one example? Thank you!

[Edit]:
Sorry, using "CDS" is misleading. I changed the title and contents to "contain more than one protein-coding genes" instead of "more than one CDS". I also change the starting position of the second protein to 3752 (was 3750) to reflect the fact. My sincere apologies.
The GFF3 file format specification doesn't care where annotations are described in the file, although it can make some things easier if the annotations are ordered by the start position:

1   T1  gene    3631    4605    .   +   .   ID=ATNG01010
1   T1  mRNA    3631    4605    .   +   .   ID=ATNG01010.1;Parent=ATNG01010
1   T1  exon    3631    3913    .   +   .   ID=ATNG01010:exon:1;Parent=ATNG01010.1
1   T1  CDS     3750    3904    .   -   0   ID=ATRV01011:CDS:1;Parent=ATRV01011.0
1   T1  CDS     3860    3913    .   +   0   ID=ATNG01010:CDS:1;Parent=ATNG01010.1
1   T1  exon    3996    4276    .   +   .   ID=ATNG01010:exon:2;Parent=ATNG01010.1
1   T1  CDS     3996    4260    .   +   2   ID=ATNG01010:CDS:2;Parent=ATNG01010.1
1   T1  exon    4486    4605    .   +   .   ID=ATNG01010:exon:3;Parent=ATNG01010.1


There are many examples in well-studied genomes of overlapping genes, so the GFF3 format needs to be flexible enough to handle these. Different genes can be encoded across the same region, but on different strands. But different genes can also be encoded on the same strand, sometimes sharing an exon.