Is There Two Options To Say The Same Thing Or Not? / Incorrect
Is there another way to say this sentence?, Is there a second way to say this sentence? / Correct
I hear a lot of Russian speakers say "Besides", Beside means "next to" most of the times.
F.e, Tom is sitting beside Jerry.
As for your question, if there's an alternative to"Stop talking about Jerry only" you can say "Let's talk about something else" or "Switch the topic".