Is it okay to lie to your friend if the secrets not yours to tell?

My friend lets call her Susie was seeing this boy.
My best friends lets call her Fran also likes this boy. It turns out this boy likes Fran more than Susie and breaks up with Susie for Fran.
Susie doesn't know that this boy has broke up with her for Fran.
Fran is scared that it's going to ruin her friendship with Susie.
She decided to keep it a secret but now someone outside our friendship group knows and there is a high chance of Susie finding out. What should I advise her to do?

& I know that what Fran did was a bit out of order. Stealing your friends boyfriend is low but fran has been there for me through so much and I feel I owe her my loyalty.
I don't want to be involved in lieing to and hurting Susie but I don't want to abandon Fran.

I'm not even sure if that makes sense? Sorry if it doesn't.
My spell checker isn't working either so I probably look like an illiterate moron.

x

lieing will just make things worse telling the truth is the best thing you can do in a friendship even if it upsets her..she will eventually get over it

I think you should stay out of it... this isnt your mess to deal with or fix...

uh, if it's not your secret to tell then sure.