<human>: I'm 26m, and the two girls I'll be mentioning are around 23-26.  I don't know absolutely, since they started recently, but Girl 1 seems more mature, so around 24/25/26 maturity-wise I'd say, Girl 2 maybe 23 in both aspects.

Let me preface this with, I know work situations are usually messy, but I know a bunch of my coworkers are dating each other, so I'm not going to rule anything out here.

I'm interested in one girl at work, that basically just started.  We have a bunch in common (from what we've managed to talk about), but I won't get into specifics just to keep anonymous.  I'm not getting any major signs from her, but we haven't been able to talk much.  Another girl is into me, it is pretty obvious, which I won't explain again for anonymity.

Girl 2 asked me to do something on a day we're both off.  But I don't want to ruin chances with Girl 1, who I won't see again until after the day off with Girl 2.  I'm unsure on the specifics, but if I do a casual lunch or something with Girl 2, does that mean I can't talk to Girl 1?  How can I say to Girl 2, that I'm not sure where I want to go with her yet?  Do I just say that?  At what point does it become "dating" or at least weird for me to talk to another girl?  Some people at work have jokingly said I talk to a lot of the girls at work, so would better advice be to stay away from both?  I don't see myself there too long, but I also don't get many girls into me to be honest, so I don't want to rule anything out without good reasons.

I know since they're both new, I could be over-reacting and way too soon, but I just prefer to tread carefully and cautiously whenever possible.

Can you summarize the given text in a few sentences?
<bot>: Girl I really like at work hasn't shown any definite signs of interest in me.  Girl I like, has.  How can I not ruin chances with the first, while keeping the other happy as well.