Hi:
Sounds promising.
Something to remember, however, is that a VC who invests in a series B round has different objectives than an angel investor, a seed investor and perhaps even in investor in a series A round. If one of the B round investors in that other company has been with that company through all of those stages, they may be a candidate for you to approach, but if they're only in at the B level, you may not interest them at this time.
That said, it may not hurt to chat with a B round investor to get on their radar. They may even point you to an earlier stage investor colleague. That should be part of the prioritization exercise you take with your potential investor pool.
Before you approach any investor, however, get your story straight around differentiation and your company's unique approach to solving a marketplace problem.
If you wish to discuss, send me a PM through Clarity for 15 free minutes.
Cheers,
Kerby

I'd pitch the exact same VC or pitch this VC's competitors.

Or call up the CEO of the company who received the investment + book a meeting to ask their advice about getting VC capitol.

If you can scare the CEO enough, they might buy you out.

I have a startup and have had a few meetings with investors.

Go another route. From my recent personal experience there was no progress after the first meeting and luckily one of the guys mentioned that they had already funded a competitor. After that i realized that all their questions were 'intelligence gathering exercises' and they had already decided not to fund me. I got a call a few days later for another meeting and realized that one of the directors was really keen to know about my project details. Probably to give give feedback to their startup. I guessed right. A few weeks later I found out he was on the board of my competitor.

So tread carefully if you know your investor has a stake in a competitor.