EPUB Exporting option (Merge paragraph styles option)

I am making book layouts and facing an issue during the Epub export. I have book chapters that use two paragraph styles. The first style is for line one, "Chapter X" and the second paragraph style is for the next line with the chapter name. I can't use the same Paragraph style for both lines because they should be formatted differently.

My question is, can you add a feature that allows using a chain of paragraph styles to create an Epub table of contents? The chain can use the very first style formatting and add the second line with the different paragraph style at the end of the first one keeping the format of the text as it was in the very first style.

To illustrate what I'm writing about:
Here is what I have now on the epub TOC after export:
First TOC line [Paragraph style 1]: "Chapter X"
Second TOC line [Paragraph style 2]: "Chapter name"

What I am excepting to get:
First TOC line [Paragraph style 1 + Paragraph style 2 (which convert its format style to style 1)]: "Chapter X. Chapter name"

So two paragraph styles are merged into the one Epub style, which allows getting a single TOC string.

And also need to make a divider between two merged paragraphs. The divider can be "." or ":" or some other character. This needs to separate "Chapter X" from the "Chapter name" to make it like "Chapter X. Chapter name" and not "Chapter X Chapter name".