Would you fix a Muslim's car

I spoke with a Christian who builds websites and he told me he would not build a website for any non-evangelical Christian religious group. In fact, he didn’t want to build a website for an alcohol company. So, this got me thinking. If you are an ‘evangelical’ Christian who believes the only way to God is through Jesus and all other religions are false:

Would you sell ice cream to an Islamic center, synagouge or scientology center?
Would you fix the bus of an Islamic center, synagouge or scientology center?
Would you create a sign for any of these groups?
Would you build their website?
Would you host an event?
Would you go door-to-door to hand out information if they paid you?

Where is the line for someone that believes these are promoting false beliefs?